Fair Value of Financial Instruments - Schedule of Carrying Value of Limited Partnerships and Commitments to Fund (Details) - USD ($) $ in Millions	Jun. 30, 2026	Dec. 31, 2025
Schedule of Carrying Value of Limited Partnerships and Commitments To Fund [Line Items]
Carrying value	$ 3,538	$ 3,484
Commitments to fund	1,837	1,916
Total limited partnerships accounted for at NAV
Schedule of Carrying Value of Limited Partnerships and Commitments To Fund [Line Items]
Carrying value	2,844	2,768
Commitments to fund	1,724	1,835
Limited partnerships accounted for at fair value
Schedule of Carrying Value of Limited Partnerships and Commitments To Fund [Line Items]
Carrying value	19	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	2,537	2,475
Commitments to fund	1,511	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	133	137
Commitments to fund	60	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	174	156
Commitments to fund	153	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	675	700
Commitments to fund	$ 112	$ 80