Shareholders' Equity - Accumulated Other Comprehensive Income by Component (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 27,363	$ 26,200
Other comprehensive income (loss) before reclassifications	(1,564)	(598)
Amounts reclassified into (out of) accumulated other comprehensive loss	(1)	(7)
Other comprehensive income (loss)	(1,565)	(605)
Ending balance	26,224	25,005
Accumulated Other Comprehensive Income (Loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(1,133)	187
Other comprehensive income (loss)	(1,565)	(605)
Ending balance	(2,698)	(418)
Net Unrealized Gains (Losses) on Cash Flow Hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(2)	57
Other comprehensive income (loss) before reclassifications	(178)	15
Amounts reclassified into (out of) accumulated other comprehensive loss	(16)	(15)
Other comprehensive income (loss)	(194)	0
Ending balance	(196)	57
Net Unrealized Gains (Losses) on Available-for-Sale Securities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(48)	848
Other comprehensive income (loss) before reclassifications	(1,288)	(413)
Amounts reclassified into (out of) accumulated other comprehensive loss	0	0
Other comprehensive income (loss)	(1,288)	(413)
Ending balance	(1,336)	435
Net Unrealized Losses on Hedges of Net Investments in Non-U.S. Subsidiaries
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	68	(204)
Other comprehensive income (loss) before reclassifications	64	135
Amounts reclassified into (out of) accumulated other comprehensive loss	0	0
Other comprehensive income (loss)	64	135
Ending balance	132	(69)
Other-Than-Temporary Impairment on Held-to-Maturity Securities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(2)	(2)
Other comprehensive income (loss) before reclassifications	0	0
Amounts reclassified into (out of) accumulated other comprehensive loss	0	0
Other comprehensive income (loss)	0	0
Ending balance	(2)	(2)
Net Unrealized Losses on Retirement Plans
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(130)	(178)
Other comprehensive income (loss) before reclassifications	0	0
Amounts reclassified into (out of) accumulated other comprehensive loss	15	8
Other comprehensive income (loss)	15	8
Ending balance	(115)	(170)
Foreign Currency Translation
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(1,019)	(334)
Other comprehensive income (loss) before reclassifications	(162)	(335)
Amounts reclassified into (out of) accumulated other comprehensive loss	0	0
Other comprehensive income (loss)	(162)	(335)
Ending balance	$ (1,181)	$ (669)