Shareholders' equity AOCI (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance – beginning of period, net of tax			$ 59,714
Balance – end of period, net of tax	$ 47,639	$ 59,318	47,639	$ 59,318
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	(5,713)	3,342	2,256	4,673
OCI, before Reclassifications, before Tax, Attributable to Parent	(3,324)	(564)	(12,898)	(2,151)
Reclassification from AOCI, Current Period, before Tax, Attributable to Parent	279	10	857	(26)
Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent	(3,045)	(554)	(12,041)	(2,177)
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	147	98	1,174	390
Balance – end of period, net of tax	(8,611)	2,886	(8,611)	2,886
Cumulative Foreign Currency Translation Adjustment [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance – beginning of period, net of tax	(2,821)	(1,323)	(2,146)	(1,637)
Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent	(966)	(414)	(1,676)	(84)
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	6	23	41	7
Balance – end of period, net of tax	(3,781)	(1,714)	(3,781)	(1,714)
Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance – beginning of period, net of tax	0	0	0	0
OCI, before Reclassifications, before Tax, Attributable to Parent	(94)	0	(94)	0
Reclassification from AOCI, Current Period, before Tax, Attributable to Parent	32	0	32	0
Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent	(62)	0	(62)	0
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	13	0	13	0
Balance – end of period, net of tax	(49)	0	(49)	0
Postretirement Benefit Liability Adjustment [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance – beginning of period, net of tax	259	(197)	240	(167)
Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent	3	4	27	(33)
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	(1)	(1)	(6)	6
Balance – end of period, net of tax	261	(194)	261	(194)
Accumulated Other Comprehensive Income (Loss) [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance – beginning of period, net of tax	(8,275)	1,822	350	2,869
Balance – end of period, net of tax	$ (12,180)	$ 978	$ (12,180)	$ 978