Shareholders' equity AOCI (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance – beginning of period, net of tax			$ 59,507
Other comprehensive income (loss), before income tax	$ (990)	$ (955)	(1,604)	$ 467
Other Comprehensive Income (Loss), Tax	(29)	(28)	(38)	104
Other Comprehensive Income (Loss), Net of Tax	(961)	(927)	(1,566)	363
Balance – end of period, net of tax	61,038	52,875	61,038	52,875
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	(4,825)	(5,659)	(4,177)	(7,279)
Balance – end of period, net of tax	(5,301)	(6,809)	(5,301)	(6,809)
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-Sale, Including Noncontrolling Interest
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Other Comprehensive Income (Loss), before Reclassifications, before Tax	(484)	(1,301)	(1,280)	305
Net Realized Gains (Losses) Reclassified from AOCI	5	(107)	(114)	(287)
Other comprehensive income (loss), before income tax	(489)	(1,194)	(1,166)	592
Other Comprehensive Income (Loss), Tax	(7)	(44)	(49)	122
Other Comprehensive Income (Loss), Net of Tax	(482)	(1,150)	(1,117)	470
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-Sale, Noncontrolling Interest
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Other Comprehensive Income (Loss), Net of Tax	(6)	0	7	0
AOCI, Liability for Future Policy Benefit, Parent
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance – beginning of period, net of tax	11	(205)	51	(75)
Balance – end of period, net of tax	66	(247)	66	(247)
AOCI, Liability for Future Policy Benefit, Including Noncontrolling Interest
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Other comprehensive income (loss), before income tax	53	(35)	0	(186)
Other Comprehensive Income (Loss), Tax	2	7	22	(14)
Other Comprehensive Income (Loss), Net of Tax	51	(42)	(22)	(172)
AOCI, Liability for Future Policy Benefit, Noncontrolling Interest
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Other Comprehensive Income (Loss), Net of Tax	(4)	0	(37)	0
AOCI, Market Risk Benefit, Instrument-Specific Credit Risk, Parent
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance – beginning of period, net of tax	(17)	(27)	(22)	(24)
Balance – end of period, net of tax	(13)	(16)	(13)	(16)
AOCI, Market Risk Benefit, Instrument-Specific Credit Risk, Including Noncontrolling Interest
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Other comprehensive income (loss), before income tax	5	11	10	8
Other Comprehensive Income (Loss), Tax	1	0	1	0
Other Comprehensive Income (Loss), Net of Tax	4	11	9	8
AOCI, Market Risk Benefit, Instrument-Specific Credit Risk, Noncontrolling Interest
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Other Comprehensive Income (Loss), Net of Tax	0	0	0	0
Cumulative Foreign Currency Translation Adjustment [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance – beginning of period, net of tax	(2,864)	(3,136)	(2,945)	(2,966)
Balance – end of period, net of tax	(3,342)	(2,920)	(3,342)	(2,920)
Accumulated Foreign Currency Adjustment Including Portion Attributable to Noncontrolling Interest
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Other Comprehensive Income (Loss), before Reclassifications, before Tax	(527)	219	(444)	45
Net Realized Gains (Losses) Reclassified from AOCI	3	4	6	7
Other comprehensive income (loss), before income tax	(530)	215	(450)	38
Other Comprehensive Income (Loss), Tax	(19)	(1)	(12)	(8)
Other Comprehensive Income (Loss), Net of Tax	(511)	216	(438)	46
Accumulated Foreign Currency Adjustment Attributable to Noncontrolling Interest
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Other Comprehensive Income (Loss), Net of Tax	(33)	0	(41)	0
Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance – beginning of period, net of tax	13	(92)	(13)	(66)
Balance – end of period, net of tax	(11)	(53)	(11)	(53)
Accumulated Gain (Loss), Cash Flow Hedge, Including Noncontrolling Interest
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Other Comprehensive Income (Loss), before Reclassifications, before Tax	(46)	57	(54)	40
Net Realized Gains (Losses) Reclassified from AOCI	(16)	7	(57)	23
Other comprehensive income (loss), before income tax	(30)	50	3	17
Other Comprehensive Income (Loss), Tax	(6)	11	1	4
Other Comprehensive Income (Loss), Net of Tax	(24)	39	2	13
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Noncontrolling Interest
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Other Comprehensive Income (Loss), Net of Tax	0	0	0	0
Postretirement Benefit Liability Adjustment [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance – beginning of period, net of tax	296	224	297	225
Balance – end of period, net of tax	297	223	297	223
Accumulated Defined Benefit Plans Adjustment Including Portion Attributable to Noncontrolling Interest
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Other comprehensive income (loss), before income tax	1	(2)	(1)	(2)
Other Comprehensive Income (Loss), Tax	0	(1)	(1)	0
Other Comprehensive Income (Loss), Net of Tax	1	(1)	0	(2)
Accumulated Defined Benefit Plans Adjustment Attributable to Noncontrolling Interest
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Other Comprehensive Income (Loss), Net of Tax	0	0	0	0
Accumulated Other Comprehensive Income (Loss) [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance – beginning of period, net of tax	(7,386)	(8,895)	(6,809)	(10,185)
Other Comprehensive Income (Loss), Net of Tax	(918)	(927)	(1,495)	363
Balance – end of period, net of tax	$ (8,304)	$ (9,822)	$ (8,304)	$ (9,822)