Shareholders' Equity - Changes in AOCI Components (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Changes in balances of each component of AOCI, net of tax
Beginning balance	$ 4,729	$ 3,803
OCI before reclassifications	(164)	563
Amounts reclassified from AOCI		(2)
Total other comprehensive income (loss), net of tax	(164)	561
Ending balance	4,879	4,144
Total AOCI
Changes in balances of each component of AOCI, net of tax
Beginning balance	(1,766)	(2,546)
Total other comprehensive income (loss), net of tax	(164)	561
Ending balance	(1,930)	(1,985)
Net unrealized gains (losses) on securities
Changes in balances of each component of AOCI, net of tax
Beginning balance	(1,241)	(2,043)
OCI before reclassifications	(178)	432
Amounts reclassified from AOCI		(2)
Total other comprehensive income (loss), net of tax	(178)	430
Ending balance	(1,419)	(1,613)
Net unrealized gains (losses) on derivatives
Changes in balances of each component of AOCI, net of tax
Beginning balance	5	3
OCI before reclassifications	0	2
Amounts reclassified from AOCI		0
Total other comprehensive income (loss), net of tax	0	2
Ending balance	5	5
Effect of changes in discount rate assumptions on certain long-duration contracts
Changes in balances of each component of AOCI, net of tax
Beginning balance	(126)	(72)
OCI before reclassifications	69	(65)
Amounts reclassified from AOCI		0
Total other comprehensive income (loss), net of tax	69	(65)
Ending balance	(57)	(137)
Effect of changes in instrument-specific credit risk on MRBs
Changes in balances of each component of AOCI, net of tax
Beginning balance	(85)	(20)
OCI before reclassifications	(37)	161
Amounts reclassified from AOCI		0
Total other comprehensive income (loss), net of tax	(37)	161
Ending balance	(122)	141
Defined benefit plans
Changes in balances of each component of AOCI, net of tax
Beginning balance	(60)	(75)
OCI before reclassifications	0	0
Amounts reclassified from AOCI		0
Total other comprehensive income (loss), net of tax	0	0
Ending balance	(60)	(75)
Foreign currency translation
Changes in balances of each component of AOCI, net of tax
Beginning balance	(258)	(338)
OCI before reclassifications	(18)	33
Amounts reclassified from AOCI		0
Total other comprehensive income (loss), net of tax	(18)	33
Ending balance	(276)	(305)
Other
Changes in balances of each component of AOCI, net of tax
Beginning balance	(1)	(1)
OCI before reclassifications	0	0
Amounts reclassified from AOCI		0
Total other comprehensive income (loss), net of tax	0	0
Ending balance	$ (1)	$ (1)