Accumulated Other Comprehensive Income (Loss) by Component (Schedule of Accumulated Other Comprehensive Income (Loss) by Component) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2023	Dec. 31, 2022		Dec. 31, 2021		Dec. 31, 2020
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Total stockholder's equity at beginning of period	[1]	$ 8,548	$ 11,105
Other comprehensive income (loss) before reclassifications		827	(2,383)		$ 216
Amounts reclassified from accumulated other comprehensive income (loss) net of tax		(99)	(145)		39
Other comprehensive income (loss) after tax (expense) benefit		926	(2,238)		177
Total stockholder's equity at end of period		9,893	8,548	[1]	11,105	[1]
Cumulative effect adjustments from changes in accounting guidance, tax			11		446		$ 622
Reclassification from AOCI, tax		26	26		(10)
Tax (expense) benefit on other comprehensive income (loss)		(235)	568		(51)
Prior to Adoption
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Total stockholder's equity at beginning of period		8,825
Total stockholder's equity at end of period			8,825
Effect of Adoption
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Total stockholder's equity at beginning of period		(277)
Total stockholder's equity at end of period			(277)
Accumulated other comprehensive income (loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Total stockholder's equity at beginning of period	[1]	(3,598)	(1,360)		(1,537)
Total stockholder's equity at end of period		(2,672)	(3,598)	[1]	(1,360)	[1]	(1,537)	[1]
Accumulated other comprehensive income (loss) | Prior to Adoption
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Total stockholder's equity at beginning of period		(3,557)	320	[1]	803	[1]
Total stockholder's equity at end of period			(3,557)		320	[1]	803	[1]
Accumulated other comprehensive income (loss) | Effect of Adoption
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Total stockholder's equity at beginning of period		(41)	(1,680)	[1]	(2,340)	[1]
Total stockholder's equity at end of period			(41)		(1,680)	[1]	(2,340)	[1]
Net unrealized gains (losses) on investments | Net unrealized gains (losses) on investments with an allowance for credit losses
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Total stockholder's equity at beginning of period		(7)	(2)		0
Other comprehensive income (loss) before reclassifications		(24)	0		(7)
Amounts reclassified from accumulated other comprehensive income (loss) net of tax		(19)	5		(5)
Other comprehensive income (loss) after tax (expense) benefit		(5)	(5)		(2)
Total stockholder's equity at end of period		(12)	(7)		(2)		0
Cumulative effect adjustments from changes in accounting guidance, tax			0		0		0
Reclassification from AOCI, tax		5	(1)		1
Tax (expense) benefit on other comprehensive income (loss)		1	1		1
Net unrealized gains (losses) on investments | Net unrealized gains (losses) on investments with an allowance for credit losses | Prior to Adoption
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Total stockholder's equity at beginning of period		(7)	(2)		0
Total stockholder's equity at end of period			(7)		(2)		0
Net unrealized gains (losses) on investments | Net unrealized gains (losses) on investments with an allowance for credit losses | Effect of Adoption
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Total stockholder's equity at beginning of period		0	0		0
Total stockholder's equity at end of period			0		0		0
Net unrealized gains (losses) on investments | Net unrealized gains and losses on other investments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Total stockholder's equity at beginning of period		(2,738)	3,359		4,346
Other comprehensive income (loss) before reclassifications		1,072	(6,223)		(906)
Amounts reclassified from accumulated other comprehensive income (loss) net of tax		(53)	(126)		81
Other comprehensive income (loss) after tax (expense) benefit		1,125	(6,097)		(987)
Total stockholder's equity at end of period		(1,613)	(2,738)		3,359		4,346
Cumulative effect adjustments from changes in accounting guidance, tax			0		(617)		(691)
Reclassification from AOCI, tax		14	21		(21)
Tax (expense) benefit on other comprehensive income (loss)		(304)	1,622		263
Net unrealized gains (losses) on investments | Net unrealized gains and losses on other investments | Prior to Adoption
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Total stockholder's equity at beginning of period		(2,738)	1,039		1,745
Total stockholder's equity at end of period			(2,738)		1,039		1,745
Net unrealized gains (losses) on investments | Net unrealized gains and losses on other investments | Effect of Adoption
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Total stockholder's equity at beginning of period		0	2,320		2,601
Total stockholder's equity at end of period			0		2,320		2,601
Pension and postretirement benefits
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Total stockholder's equity at beginning of period		(591)	(604)		(848)
Other comprehensive income (loss) before reclassifications		39	(11)		207
Amounts reclassified from accumulated other comprehensive income (loss) net of tax		(27)	(24)		(37)
Other comprehensive income (loss) after tax (expense) benefit		66	13		244
Total stockholder's equity at end of period		(525)	(591)		(604)		(848)
Cumulative effect adjustments from changes in accounting guidance, tax			0		0		0
Reclassification from AOCI, tax		7	6		10
Tax (expense) benefit on other comprehensive income (loss)		(17)	(3)		(65)
Pension and postretirement benefits | Prior to Adoption
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Total stockholder's equity at beginning of period		(591)	(604)		(848)
Total stockholder's equity at end of period			(591)		(604)		(848)
Pension and postretirement benefits | Effect of Adoption
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Total stockholder's equity at beginning of period		0	0		0
Total stockholder's equity at end of period			0		0		0
Cumulative impact of changes in discount rates used to measure long duration contracts
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Total stockholder's equity at beginning of period		(41)	(4,000)		(4,941)
Other comprehensive income (loss) before reclassifications		(318)	3,959		941
Amounts reclassified from accumulated other comprehensive income (loss) net of tax		0	0		0
Other comprehensive income (loss) after tax (expense) benefit		(318)	3,959		941
Total stockholder's equity at end of period		(359)	(41)		(4,000)		(4,941)
Cumulative effect adjustments from changes in accounting guidance, tax			11		1,063		1,313
Reclassification from AOCI, tax					0
Tax (expense) benefit on other comprehensive income (loss)		85	(1,052)		(250)
Cumulative impact of changes in discount rates used to measure long duration contracts | Prior to Adoption
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Total stockholder's equity at beginning of period		0	0		0
Total stockholder's equity at end of period			0		0		0
Cumulative impact of changes in discount rates used to measure long duration contracts | Effect of Adoption
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Total stockholder's equity at beginning of period		(41)	(4,000)		(4,941)
Total stockholder's equity at end of period			(41)		(4,000)		(4,941)
Cumulative foreign currency translation adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Total stockholder's equity at beginning of period		(221)	(113)		(94)
Other comprehensive income (loss) before reclassifications		58	(108)		(19)
Amounts reclassified from accumulated other comprehensive income (loss) net of tax		0	0		0
Other comprehensive income (loss) after tax (expense) benefit		58	(108)		(19)
Total stockholder's equity at end of period		(163)	(221)		(113)		(94)
Cumulative effect adjustments from changes in accounting guidance, tax			0		0		0
Reclassification from AOCI, tax		0	0		0
Tax (expense) benefit on other comprehensive income (loss)		0	0		0
Cumulative foreign currency translation adjustment | Prior to Adoption
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Total stockholder's equity at beginning of period		(221)	(113)		(94)
Total stockholder's equity at end of period			(221)		(113)		(94)
Cumulative foreign currency translation adjustment | Effect of Adoption
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Total stockholder's equity at beginning of period		$ 0	0		0
Total stockholder's equity at end of period			$ 0		$ 0		$ 0

[1] As of January 1, 2023, the Company adopted ASU 2018-12, Financial Services-Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts (ASU 2018-12) using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.