Accumulated Other Comprehensive Income (Loss) - Changes in AOCI, including Reclassification Adjustments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Before-Tax Amount
Available-for-sale securities, fixed maturities	$ (208)	$ 899	$ (6,569)
Adjustments for amounts recognized in Net gains (losses) in the Consolidated Statements of Operations	26	25	78
Change in unrealized gains/losses on available-for-sale securities	(182)	924	(6,491)
Derivatives	18	(43)	66
Adjustments for amounts recognized in Net investment income in the Condensed Consolidated Statements of Operations	(16)	(18)	(20)
Change in unrealized gains (losses) on derivatives	2	(61)	46
Change in current discount rate	103	(33)	290
Amortization of prior service cost recognized in Operating expenses in the Consolidated Statements of Operations	(1)	(1)
Change in pension and other postretirement benefits liability	(1)	(1)	0
Other comprehensive income (loss), before tax	(78)	829	(6,155)
Income Tax (Benefit)
Available-for-sale securities, fixed maturities	44	(189)	1,380
Adjustments for amounts recognized in Net realized capital gains (losses) in the Condensed Consolidated Statements of Operations	(5)	(5)	(16)
Change in unrealized gains/losses on available-for-sale securities	39	(194)	1,364
Derivatives	(4)	9	(14)
Adjustments related to effective cash flow hedges for amounts recognized in Net investment income in the Consolidated Statements of Operations	3	4	4
Change in unrealized gains (losses) on derivatives	(1)	13	(10)
Change in current discount rate	(22)	7	(61)
Amortization of prior service cost recognized in Operating expenses in the Condensed Consolidated Statements of Operations	0	0
Change in pension and other postretirement benefits liability	0	0
Change in Other comprehensive income (loss)	16	(174)	1,293
After-Tax Amount
Available-for-sale securities, fixed maturities	(164)	710	(5,189)
Adjustments for amounts recognized in Net realized capital gains (losses) in the Condensed Consolidated Statements of Operations	21	20	62
Change in unrealized gains/losses on available-for-sale securities	(143)	730	(5,127)
Derivatives	14	(34)	52
Adjustments related to effective cash flow hedges for amounts recognized in Net investment income in the Consolidated Statements of Operations	(13)	(14)	(16)
Change in unrealized gains (losses) on derivatives	1	(48)	36
Change in current discount rate	81	(26)	229
Amortization of prior service cost recognized in Operating expenses in the Condensed Consolidated Statements of Operations	(1)	(1)
Change in pension and other postretirement benefits liability	(1)	(1)
Other comprehensive income (loss), after tax	$ (62)	$ 655	$ (4,862)