Equity Activity - AOCI Rollforward (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Accumulated Other Comprehensive Income (Loss) (net of tax)
Balance at the Beginning of the Period	$ 22,067	$ 20,688	$ 20,727	$ 20,985
Other comprehensive income/(loss)	350	172	2,035	12
Balance at the End of the Period	22,357	21,334	22,357	21,334
Accumulated Other Comprehensive Income/(Loss)
Accumulated Other Comprehensive Income (Loss) (net of tax)
Balance at the Beginning of the Period	(27,652)	(28,757)	(29,337)	(28,597)
Other comprehensive income before reclassifications			382	(1,242)
Amount reclassified from accumulated other comprehensive income			1,654	1,255
Other comprehensive income/(loss)	350	172	2,035	12
Balance at the End of the Period	(27,302)	(28,584)	(27,302)	(28,584)
Net Unrealized Gains/(Losses) on Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss) (net of tax)
Balance at the Beginning of the Period			(456)	(179)
Other comprehensive income before reclassifications	82	(24)	196	(186)
Amount reclassified from accumulated other comprehensive income			211	(27)
Other comprehensive income/(loss)	106	(75)	407	(212)
Balance at the End of the Period	(49)	(391)	(49)	(391)
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) (net of tax)
Balance at the Beginning of the Period			(4,665)	(3,700)
Other comprehensive income before reclassifications			160	(1,094)
Other comprehensive income/(loss)	(234)	(192)	160	(1,094)
Balance at the End of the Period	(4,505)	(4,794)	(4,505)	(4,794)
Net Change Retirement-Related Benefit Plans
Accumulated Other Comprehensive Income (Loss) (net of tax)
Balance at the Beginning of the Period			(24,216)	(24,718)
Other comprehensive income before reclassifications			26	37
Amount reclassified from accumulated other comprehensive income			1,442	1,281
Other comprehensive income/(loss)	478	440	1,469	1,319
Balance at the End of the Period	(22,747)	(23,399)	(22,747)	(23,399)
Net Unrealized Gains/(Losses) on Available-For-Sale Securities
Accumulated Other Comprehensive Income (Loss) (net of tax)
Balance at the Beginning of the Period			0	0
Other comprehensive income before reclassifications	0	(1)	0	0
Other comprehensive income/(loss)	0	(1)	0	0
Balance at the End of the Period	$ (1)	$ 0	$ (1)	$ 0