Fair Value of Financial Instruments - Schedule of Carrying Value of Limited Partnerships and Commitments to Fund (Details) - USD ($) $ in Millions	Mar. 31, 2026	Dec. 31, 2025
Schedule of Carrying Value of Limited Partnerships and Commitments To Fund [Line Items]
Carrying value	$ 3,528	$ 3,484
Commitments to fund	1,905	1,916
Total limited partnerships accounted for at NAV
Schedule of Carrying Value of Limited Partnerships and Commitments To Fund [Line Items]
Carrying value	2,823	2,768
Commitments to fund	1,810	1,835
Limited partnerships accounted for at fair value
Schedule of Carrying Value of Limited Partnerships and Commitments To Fund [Line Items]
Carrying value	20	16
Commitments to fund	1	1
Private equity and credit funds \| Total limited partnerships accounted for at NAV
Schedule of Carrying Value of Limited Partnerships and Commitments To Fund [Line Items]
Carrying value	2,520	2,475
Commitments to fund	1,590	1,619
Real estate funds \| Total limited partnerships accounted for at NAV
Schedule of Carrying Value of Limited Partnerships and Commitments To Fund [Line Items]
Carrying value	132	137
Commitments to fund	63	65
Infrastructure funds \| Total limited partnerships accounted for at NAV
Schedule of Carrying Value of Limited Partnerships and Commitments To Fund [Line Items]
Carrying value	171	156
Commitments to fund	157	151
Limited partnerships accounted for under equity method of accounting
Schedule of Carrying Value of Limited Partnerships and Commitments To Fund [Line Items]
Carrying value	685	700
Commitments to fund	$ 94	$ 80