Equity Activity - AOCI Rollforward (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Accumulated Other Comprehensive Income (Loss) (net of tax)
Balance at the Beginning of the Period	$ 21,513	$ 20,128	$ 20,727	$ 20,985
Other comprehensive income/(loss)	605	527	1,685	(160)
Balance at the End of the Period	22,067	20,688	22,067	20,688
Accumulated Other Comprehensive Income/(Loss)
Accumulated Other Comprehensive Income (Loss) (net of tax)
Balance at the Beginning of the Period	(28,257)	(29,283)	(29,337)	(28,597)
Other comprehensive income before reclassifications			532	(1,025)
Amount reclassified from accumulated other comprehensive income			1,153	866
Other comprehensive income/(loss)	605	527	1,685	(160)
Balance at the End of the Period	(27,652)	(28,757)	(27,652)	(28,757)
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	(26)	(26)	114	(162)
Amount reclassified from accumulated other comprehensive income			187	25
Other comprehensive income/(loss)	42	(70)	301	(137)
Balance at the End of the Period	(155)	(316)	(155)	(316)
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			393	(902)
Other comprehensive income/(loss)	72	139	393	(902)
Balance at the End of the Period	(4,271)	(4,602)	(4,271)	(4,602)
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			25	38
Amount reclassified from accumulated other comprehensive income			966	841
Other comprehensive income/(loss)	491	457	991	879
Balance at the End of the Period	(23,225)	(23,839)	(23,225)	(23,839)
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	1
Other comprehensive income/(loss)	0	1	0	1
Balance at the End of the Period	$ (1)	$ 1	$ (1)	$ 1