delivered the opinion of the Court.
The issue in this case is the proper interpretation of a 1981 divorce decree that divided, among other assets, retirement benefits stemming from one spouse’s employment both during and after the marriage. The trial court held that the
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divorce decree awarded the non-employee spouse, a specific percentage of the retirement benefits valued at the date of divorce. The court of appeals reversed, concluding that the decree unambiguously awarded the non-employee spouse a percentage of the total amount of the benefits on the date of retirement.
I. Background
Kenda Carolyn Treadway and George Payton Shanks married in 1962. George started working for American Airlines in 1966 and began participating in American’s retirement program the following year. The program included both a defined benefit plan and a defined contribution plan. 1 George continued to work for American until his retirement in 1998.
George and Kenda divorced in 1981. In the divorce decree, the district court awarded Kenda a twenty-five percent interest in George’s retirement benefits, and neither party appealed the judgment. The relevant portions of the decree provide:
The Court finds that [George] has earned certain employee benefits under a pension plan arising out of past employment as an employee of American Airlines.
[Kenda] is awarded a “pro-rata interest” (as hereinafter defined) of any and all sums received or paid to [George] from such pension plan and such sum or sums shall be payable to [Kenda] if, as and when paid by American Airlines or the trustee of such plan to [George] as pension or retirement employee benefits existing because of [George’s] employment.
IT IS DECREED that [Kenda’s] “pro-rata interest” shall be defined as that sum of money equal to 25% of the total sum or sums paid or to be paid to [George] from such pension or retirement plan.
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IT IS FURTHER DECREED that all remaining right, title and interest in and to such American Airlines pension and/or retirement plan shall be and is hereby set aside to [George].
On March 9, 1998, approximately two months before his scheduled retirement date, George filed a Motion to Sign Qualified Domestic Relations Order (“QDRO”). See Tex. Fam.Code § 9.102. In his motion, George proposed that the court calculate the value of both the defined benefit and defined contribution plans as of the date of divorce in awarding Kenda her twenty-five percent interest. In response, Kenda asserted that res judicata barred the attempted collateral attack. She requested that the district court sign her proposed QDRO, awarding her twenty-five percent of the total amount of the benefits to be paid to George.
The district court signed two QDROs— George’s QDRO dividing the defined benefit plan valued at the date of divorce and Kenda’s QDRO dividing both plans valued as of the date that George actually re *446 ceived payment. In light of the inconsistent orders, George moved for reconsideration. The court granted George’s motion, vacated Kenda’s QDRO, and entered another QDRO valuing the defined contribution plan at the date of divorce. Kenda appealed.
The court of appeals reversed the judgment, concluding that the trial court’s QDROs impermissibly altered the substantive division of property made in the original divorce decree.
II. Dividing Retirement Benefits
We begin with an overview of the law that was in effect in this area at the time the decree was entered to demonstrate the complexities involved in dividing retirement benefits upon divorce. Our decisions focused first on the recognition of pension interests as community property rights and then on the separate issues of apportionment and valuation of benefits. In
Cearley v. Cearley,
we considered whether future pension benefits constitute eommu-nity property rights subject to equitable division upon divorce.
The 1983 case
Berry v. Berry,
III. Interpreting the Divorce Decree
Notwithstanding the state of the law at the time the divorce decree was entered, this case does not involve a direct appeal, and we must interpret the decree to determine not what the trial court should have done but, if possible, what the court actually did. When interpreting a divorce decree, courts apply the general rules regarding construction of judgments.
Wilde v. Murchie,
The decree in question identifies George’s pension plan as “arising out of past employment,” but then states that Kenda is entitled to “a ‘pro rata interest’ ... of any and all sums received or paid to [George] from such pension plan.... ” The decree also defines “pro rata interest” as “25% of the total sum or sums paid or to be paid to [George] from such pension or retirement plan.” The decree does not set out a specific Taggart-like formula to be used in calculating Kenda’s interest.
The court of appeals concluded, and we agree, that the decree is unambiguous, and Kenda should receive twenty-five percent of George’s total retirement benefits. The phrase “arising out of
past
employment as an employee of American Airlines” (emphasis added) does not render the decree ambiguous, as George argues; rather, it merely serves to identify more specifically the property that is being divided (i.e., George’s retirement plan).
4
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As noted by the court of appeals, the trial court awarded Kenda an interest of all sums received under such
plan,
not an interest of presently accrued benefits under such plan.
Viewing the division of the plan benefits in light of the decree as a whole, the fact that the court awarded Kenda only a twenty-five percent interest in the plan also supports our interpretation. Trial judges must carefully review all community assets in making a “just and right” division of those assets, and the retirement benefits were one of the assets considered in this case.
See Busby v. Busby,
It is true, as George points out, that Texas law prohibits courts from divesting spouses of their separate property.
Eggemeyer v. Eggemeyer,
Such an analysis is also problematic because the fact that the district court erro
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neously applied the law when it entered the divorce decree does not alter the decree’s plain language. In
Baxter,
which was decided after
Berry,
the divorce decree in question awarded the non-employee spouse “37 1/2% of [the employee spouse’s] gross benefits, if, as and when he received them. The decree also provided that [the non-employee spouse] was to receive 37 1/2% of the total benefits that [the employee spouse] received each month.”
Kenda argues that the district court cannot change the substantive division of property made in the original decree. We agree. While the court may enter a “clarifying order” to enforce compliance with an insufficiently specific decree, Tex. Fam. Code § 9.008(b), a court “may not amend, modify, alter, or change the division of property made or approved in the decree of divorce.”
Id.
§ 9.007(a). The original decree in this case is unambiguous, and the trial court had no authority to enter an order altering or modifying the original disposition of property.
Id.; Pierce v. Pierce,
IV. Conclusion
The divorce decree is unambiguous and awarded Kenda Treadway twenty-five percent of George Shanks’s total retirement benefits. The court of appeals was correct in reversing the district court’s judgment, and we therefore affirm the judgment of the court of appeals.
Notes
. Generally, an employee participating in a defined benefit plan will receive a future benefit based on a specified formula that often takes into account earnings, length of service, or both. Brown, Comment, An Interdisciplinary Analysis of the Division of Pension Benefits in Divorce and Post-Judgment Partition Actions: Cures for the Inequities in Berry v. Berry, 37 Baylor L.Rev. 107, 115-16 (1985). A defined contribution plan, on the other hand, is funded by contributions of a specified amount that are invested or placed in a trust fund, and the employee is entitled upon retirement to those contributions plus the earnings thereon. Id. at 113.
. Pension plan benefits become vested when the employee has an unconditional ownership interest in them; that is, the employee has the right to receive the accrued benefits upon retirement whether or not he is working for the same employer. Brown, 37 Baylor L.Rev. at 119. In contrast, pension benefits are “matured'' when the employee is entitled to "immediate collection and enjoyment.'' Id.
. The
Berry
decision altered this formula.
. Although George’s retirement benefits include both a defined benefit plan and a defined contribution plan, the decree referred to *448 them as a single plan. Because this is not a direct appeal, it is unnecessary to address at length the myriad differences between the two types of plans. Nevertheless, trial courts should take into serious consideration the kind of plan at issue when dividing and valuing retirement benefits. See supra note 3; Brown, 37 Baylor L.Rev. at 134-36, 156-62.
. We reiterate that even after Berry was decided, concerns about invading separate property remained. Brown, 37 Baylor L.Rev. at 152-62.
. We recognize the importance of safeguarding individual property rights, but significantly, it was not until 1977 in
Eggemeyer
that this Court expressly and unequivocally held that a court cannot divest a spouse of his or her separate property upon divorce.
Eggemeyer,
. We note, however, that we disagree with the court of appeals' conclusion in this case that the phrase "if, as, and when received” is "a term of art evidencing an intent to value a pension plan at the time of receipt rather than at the time of divorce.”
