Shares and Stockholders' Equity - Schedule of Reclassifications Out of AOCI (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net investment income	$ 1,341	$ 1,224
Realized gain (loss)	(248)	(57)
Benefits	1,769	1,739
Income (loss) before taxes	(591)	823
Income tax benefit (expense)	152	(166)
Net income (loss)	(439)	657
Reclassification out of Accumulated Other Comprehensive Income | Unrealized Gain (Loss) on Fixed Maturity AFS Securities and Certain Other Investments
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Realized gain (loss)	(27)	(50)
Benefits	7	(1)
Income (loss) before taxes	(20)	(51)
Income tax benefit (expense)	4	11
Net income (loss)	(16)	(40)
Reclassification out of Accumulated Other Comprehensive Income | Unrealized Gain (Loss) on Derivative Instruments
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net investment income	15	15
Realized gain (loss)	3	0
Income (loss) before taxes	18	15
Income tax benefit (expense)	(4)	(3)
Net income (loss)	$ 14	$ 12