Shareholders' equity AOCI (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022	Dec. 31, 2021
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance – beginning of period, net of tax	$ 50,519
Balance – end of period, net of tax	52,987	$ 55,716
Current discount rate on future policy benefits	(151)	435
OCI, Liability for Future Policy Benefit, Gain (Loss), after Reclassification Adjustment, Tax, Parent	21	(33)
AOCI, Liability for Future Policy Benefit, after Tax	(205)	(997)	$ (75)	$ (1,399)
AOCI, Market Risk Benefit, Instrument-Specific Credit Risk, after Tax	(27)	(34)	$ (24)	$ (57)
Instrument-specific credit risk on market risk benefits	(3)	23
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance – beginning of period, net of tax	(7,279)	2,256
OCI, before Reclassifications, before Tax, Attributable to Parent	1,606	(4,788)
Reclassification from AOCI, Current Period, before Tax, Attributable to Parent	180	136
Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent	1,786	(4,652)
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	(166)	812
Balance – end of period, net of tax	(5,659)	(1,584)
Cumulative Foreign Currency Translation Adjustment [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance – beginning of period, net of tax	(2,966)	(2,114)
OCI, before Reclassifications, before Tax, Attributable to Parent	(174)	0
Reclassification from AOCI, Current Period, before Tax, Attributable to Parent	(3)	0
Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent	(177)	67
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	7	4
Balance – end of period, net of tax	(3,136)	(2,043)
Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance – beginning of period, net of tax	(66)	0
OCI, before Reclassifications, before Tax, Attributable to Parent	(17)	0
Reclassification from AOCI, Current Period, before Tax, Attributable to Parent	(16)	0
Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent	(33)	0
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	7	0
Balance – end of period, net of tax	(92)	0
Postretirement Benefit Liability Adjustment [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance – beginning of period, net of tax	225	240
Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent	0	19
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	(1)	(4)
Balance – end of period, net of tax	224	255
Accumulated Other Comprehensive Income (Loss) [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance – beginning of period, net of tax	(10,185)	(1,074)
Balance – end of period, net of tax	$ (8,895)	$ (4,403)