Equity Activity - AOCI Rollforward (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Accumulated Other Comprehensive Income (Loss) (net of tax)
Balance at the Beginning of the Period	$ 20,688	$ 17,776	$ 20,985	$ 16,929
Other comprehensive income/(loss)	172	(245)	12	404
Balance at the End of the Period	21,334	18,096	21,334	18,096
Accumulated Other Comprehensive Income/(Loss)
Accumulated Other Comprehensive Income (Loss) (net of tax)
Balance at the Beginning of the Period	(28,757)	(28,841)	(28,597)	(29,490)
Other comprehensive income before reclassifications			(1,242)	(916)
Amount reclassified from accumulated other comprehensive income			1,255	1,320
Other comprehensive income/(loss)	172	(245)	12	404
Balance at the End of the Period	(28,584)	(29,086)	(28,584)	(29,086)
Net Unrealized Gains/(Losses) on Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss) (net of tax)
Balance at the Beginning of the Period			(179)	284
Other comprehensive income before reclassifications	(24)	(329)	(186)	(601)
Amount reclassified from accumulated other comprehensive income			(27)	315
Other comprehensive income/(loss)	(75)	36	(212)	(287)
Balance at the End of the Period	(391)	(3)	(391)	(3)
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) (net of tax)
Balance at the Beginning of the Period			(3,700)	(3,690)
Other comprehensive income before reclassifications			(1,094)	(405)
Other comprehensive income/(loss)	(192)	(618)	(1,094)	(405)
Balance at the End of the Period	(4,794)	(4,095)	(4,794)	(4,095)
Net Change Retirement-Related Benefit Plans
Accumulated Other Comprehensive Income (Loss) (net of tax)
Balance at the Beginning of the Period			(24,718)	(26,083)
Other comprehensive income before reclassifications			37	89
Amount reclassified from accumulated other comprehensive income			1,281	1,005
Other comprehensive income/(loss)	440	335	1,319	1,095
Balance at the End of the Period	(23,399)	(24,988)	(23,399)	(24,988)
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	(1)	2	0	1
Other comprehensive income/(loss)	(1)	2	0	1
Balance at the End of the Period	$ 0	$ 0	$ 0	$ 0