Segment Information - Reconciliation of Income (Loss) from Operations by Segment to Consolidated Net Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Segment Reporting Information [Line Items]
Operating revenues	$ 3,103.0	$ 4,089.0	$ 11,464.0	$ 7,981.0
Interest credited	887.0	808.0	2,559.0	2,341.0
Interest and debt expense	39.0	46.0	119.0	142.0
Total federal income tax expense (benefit)	33.0	(195.0)	11.0	138.0
Reconciliation of total income (loss) from operations to net income (loss):
Net annuity product features, pre-tax	410.0	(347.0)	666.0	1,066.0
Net life insurance product features, pre-tax	(28.0)	(132.0)	(63.0)	(277.0)
Credit loss-related adjustments, pre-tax	(38.0)	(88.0)	(91.0)	(123.0)
Investment gains (losses), pre-tax	14.0	(57.0)	(30.0)	(317.0)
Changes in the fair value of reinsurance-related embedded derivatives, trading securities and certain mortgage loans, pre-tax	(232.0)	(416.0)	(464.0)	(326.0)
GLB rider fees ceded to LNBAR, pre-tax	(235.0)	(242.0)	(704.0)	(703.0)
Gains (losses) on other non-financial assets -sale of subsidiaries/businesses, pre-tax		0.0		481.0
Other items, pre-tax	(99.0)	(19.0)	(130.0)	(113.0)
Income tax benefit (expense) related to the above pre-tax items	44.0	276.0	165.0	39.0
Net income (loss)	275.0	(600.0)	463.0	818.0
Changes in non-performance	199.0	(679.0)	23.0	185.0
Legal fees	(9.0)		(9.0)
Severance expense for workforce realignment, before tax	(5.0)	(16.0)	(13.0)	(72.0)
Transaction and integration costs for acquisitions or divestiture, before tax		(2.0)		(28.0)
Deferred compensation mark-to-market adjustment, before tax	(9.0)	(1.0)	(14.0)	(10.0)
Certain legal accruals, before tax				(3.0)
Wealth Management Business
Reconciliation of total income (loss) from operations to net income (loss):
Transaction and integration costs for acquisitions or divestiture, before tax			(18.0)
Captive Reinsurance Subsidiaries
Reconciliation of total income (loss) from operations to net income (loss):
Transaction and integration costs for acquisitions or divestiture, before tax	(54.0)		(54.0)
Embedded Derivative Instruments
Reconciliation of total income (loss) from operations to net income (loss):
Gain (loss) on derivatives	49.0	152.0	135.0	370.0
Qualifying Hedges
Reconciliation of total income (loss) from operations to net income (loss):
Gain (loss) on derivatives	162.0	180.0	508.0	511.0
Operating Segments and Corporate Non Segment
Segment Reporting Information [Line Items]
Operating revenues	3,103.0	4,089.0	11,464.0	7,981.0
Benefits and policyholder liability remeasurement (gain) loss	402.0	1,512.0	3,716.0	414.0
Interest credited	887.0	808.0	2,559.0	2,341.0
Commissions	544.0	515.0	1,620.0	1,527.0
General and administrative expenses	619.0	610.0	1,830.0	1,809.0
Interest and debt expense	39.0	46.0	119.0	142.0
Other	95.0	95.0	321.0	447.0
Total operating expenses	2,586.0	3,586.0	10,165.0	6,680.0
Total federal income tax expense (benefit)	78.0	78.0	185.0	210.0
Total income (loss) from operations	439.0	425.0	1,114.0	1,091.0
Other Operations
Segment Reporting Information [Line Items]
Operating revenues	58.0	55.0	135.0	114.0
Benefits and policyholder liability remeasurement (gain) loss	2.0	3.0	8.0	3.0
Interest credited	22.0	8.0	49.0	26.0
Commissions	3.0	0.0	3.0	0.0
General and administrative expenses	49.0	48.0	132.0	131.0
Interest and debt expense	39.0	46.0	119.0	142.0
Other	0.0	(1.0)	0.0	(1.0)
Total operating expenses	115.0	104.0	311.0	301.0
Total federal income tax expense (benefit)	(15.0)	(11.0)	(35.0)	(35.0)
Total income (loss) from operations	(42.0)	(38.0)	(141.0)	(152.0)
Reconciliation of total income (loss) from operations to net income (loss):
Gains (losses) on other non-financial assets -sale of subsidiaries/businesses, pre-tax		0.0		481.0
Annuities | Operating Segments
Segment Reporting Information [Line Items]
Operating revenues	1,142.0	1,101.0	3,390.0	3,421.0
Benefits and policyholder liability remeasurement (gain) loss	23.0	36.0	79.0	103.0
Interest credited	459.0	400.0	1,318.0	1,130.0
Commissions	327.0	285.0	917.0	808.0
General and administrative expenses	130.0	123.0	381.0	358.0
Interest and debt expense	0.0	0.0	0.0	0.0
Other	(39.0)	(9.0)	(64.0)	185.0
Total operating expenses	900.0	835.0	2,631.0	2,584.0
Total federal income tax expense (benefit)	32.0	39.0	100.0	135.0
Total income (loss) from operations	210.0	227.0	659.0	702.0
Reconciliation of total income (loss) from operations to net income (loss):
Gains (losses) on other non-financial assets -sale of subsidiaries/businesses, pre-tax		0.0		0.0
Life Insurance | Operating Segments
Segment Reporting Information [Line Items]
Operating revenues	1,247.0	1,249.0	3,676.0	3,748.0
Benefits and policyholder liability remeasurement (gain) loss	620.0	550.0	1,976.0	2,005.0
Interest credited	231.0	229.0	673.0	677.0
Commissions	66.0	113.0	244.0	331.0
General and administrative expenses	132.0	135.0	392.0	414.0
Interest and debt expense	0.0	0.0	0.0	0.0
Other	94.0	60.0	270.0	136.0
Total operating expenses	1,143.0	1,087.0	3,555.0	3,563.0
Total federal income tax expense (benefit)	16.0	29.0	6.0	25.0
Total income (loss) from operations	88.0	133.0	115.0	160.0
Reconciliation of total income (loss) from operations to net income (loss):
Gains (losses) on other non-financial assets -sale of subsidiaries/businesses, pre-tax		0.0		0.0
Transaction and integration costs for acquisitions or divestiture, before tax	(22.0)		(22.0)
Group Protection | Operating Segments
Segment Reporting Information [Line Items]
Operating revenues	318.0	1,353.0	3,274.0	(273.0)
Benefits and policyholder liability remeasurement (gain) loss	(243.0)	923.0	1,653.0	(1,697.0)
Interest credited	1.0	1.0	1.0	3.0
Commissions	119.0	89.0	372.0	312.0
General and administrative expenses	225.0	219.0	674.0	653.0
Interest and debt expense	0.0	0.0	0.0	0.0
Other	37.0	42.0	101.0	113.0
Total operating expenses	139.0	1,274.0	2,801.0	(616.0)
Total federal income tax expense (benefit)	38.0	17.0	99.0	72.0
Total income (loss) from operations	141.0	62.0	374.0	271.0
Reconciliation of total income (loss) from operations to net income (loss):
Gains (losses) on other non-financial assets -sale of subsidiaries/businesses, pre-tax		0.0		0.0
Retirement Plan Services | Operating Segments
Segment Reporting Information [Line Items]
Operating revenues	338.0	331.0	989.0	971.0
Benefits and policyholder liability remeasurement (gain) loss	0.0	0.0	0.0	0.0
Interest credited	174.0	170.0	518.0	505.0
Commissions	29.0	28.0	84.0	76.0
General and administrative expenses	83.0	85.0	251.0	253.0
Interest and debt expense	0.0	0.0	0.0	0.0
Other	3.0	3.0	14.0	14.0
Total operating expenses	289.0	286.0	867.0	848.0
Total federal income tax expense (benefit)	7.0	4.0	15.0	13.0
Total income (loss) from operations	$ 42.0	41.0	$ 107.0	110.0
Reconciliation of total income (loss) from operations to net income (loss):
Gains (losses) on other non-financial assets -sale of subsidiaries/businesses, pre-tax		$ 0.0		$ 0.0