Shareholders' Equity - Accumulated Other Comprehensive Income/(Loss), Net of Tax (Detail) - 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]
Beginning balance			$ 109,926
Other comprehensive income/(loss) adjustments, net of tax	$ 82	$ (67)	196	$ (522)
Ending balance	119,290	106,297	119,290	106,297
Currency translation
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(769)	(712)	(738)	(696)
Other comprehensive income/(loss) adjustments, net of tax	26	(20)	(5)	(36)
Ending balance	(743)	(732)	(743)	(732)
Debt valuation adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	1,417	(735)	(511)	(833)
Other comprehensive income/(loss) adjustments, net of tax	673	67	2,601	165
Ending balance	2,090	(668)	2,090	(668)
Pension and postretirement liabilities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(315)	(361)	(327)	(368)
Other comprehensive income/(loss) adjustments, net of tax	(2)	0	10	7
Ending balance	(317)	(361)	(317)	(361)
Available-for-sale securities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(2,287)	(81)	(492)	463
Other comprehensive income/(loss) adjustments, net of tax	(615)	(114)	(2,410)	(658)
Ending balance	(2,902)	(195)	(2,902)	(195)
Accumulated other comprehensive income/(loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(1,954)	(1,889)	(2,068)	(1,434)
Other comprehensive income/(loss) adjustments, net of tax	82	(67)	196	(522)
Ending balance	$ (1,872)	$ (1,956)	$ (1,872)	$ (1,956)