Accumulated Other Comprehensive Income Loss - AOCI Rollforward (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance			$ 16,447
OCI, net of tax	$ 196	$ (71)	502	$ (219)
Ending balance	17,518	15,680	17,518	15,680
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(1,237)	(1,642)	(1,539)	(1,482)
OCI before reclassifications	237	(184)	610	(393)
Amounts reclassified from AOCI	26	70	36	77
OCI, before tax	263	(114)	646	(316)
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	(55)	24	(136)	66
OCI, net of tax	208	(90)	510	(250)
Ending balance	(1,029)	(1,732)	(1,029)	(1,732)
AOCI, Gain (Loss), Debt Securities, Available-for-sale, with Allowance for Credit Loss, Parent
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(6)	(7)	(6)	(8)
OCI before reclassifications	1	0	1	1
Amounts reclassified from AOCI	0	0	0	0
OCI, before tax	1	0	1	1
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	0	0	0	0
OCI, net of tax	1	0	1	1
Ending balance	(5)	(7)	(5)	(7)
Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	40	21	40	21
OCI before reclassifications	(40)	11	(36)	11
Amounts reclassified from AOCI	(3)	0	(7)	0
OCI, before tax	(43)	11	(43)	11
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	9	(2)	9	(2)
OCI, net of tax	(34)	9	(34)	9
Ending balance	6	30	6	30
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	29	36	29	37
OCI before reclassifications	20	(1)	20	(3)
Amounts reclassified from AOCI	0	0	0	0
OCI, before tax	20	(1)	20	(3)
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	(4)	0	(4)	1
OCI, net of tax	16	(1)	16	(2)
Ending balance	45	35	45	35
AOCI, Liability for Future Policy Benefit, Parent
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	30	30	33	25
OCI before reclassifications	(1)	6	(5)	13
Amounts reclassified from AOCI	0	0	0	0
OCI, before tax	(1)	6	(5)	13
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	0	(1)	1	(3)
OCI, net of tax	(1)	5	(4)	10
Ending balance	29	35	29	35
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(1,436)	(1,435)	(1,443)	(1,442)
OCI before reclassifications	(1)	(1)	0	1
Amounts reclassified from AOCI	9	9	16	16
OCI, before tax	8	8	16	17
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	(2)	(2)	(3)	(4)
OCI, net of tax	6	6	13	13
Ending balance	(1,430)	(1,429)	(1,430)	(1,429)
AOCI Attributable to Parent [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(2,580)	(2,997)	(2,886)	(2,849)
OCI before reclassifications	216	(169)	590	(370)
Amounts reclassified from AOCI	32	79	45	93
OCI, before tax	248	(90)	635	(277)
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	(52)	19	(133)	58
OCI, net of tax	196	(71)	502	(219)
Ending balance	$ (2,384)	$ (3,068)	$ (2,384)	$ (3,068)

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount before tax and reclassification adjustments of other comprehensive income (loss) attributable to parent.

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Amount before tax of other comprehensive income (loss) attributable to parent entity.

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Amount of tax expense (benefit) allocated to other comprehensive income (loss) attributable to parent entity.

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