Equity Activity - AOCI Rollforward (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Accumulated Other Comprehensive Income (Loss) (net of tax)
Balance at the Beginning of the Period	$ 20,985	$ 16,929
Other comprehensive income/(loss)	(686)	308
Balance at the End of the Period	20,128	16,607
Accumulated Other Comprehensive Income/(Loss)
Accumulated Other Comprehensive Income (Loss) (net of tax)
Balance at the Beginning of the Period	(28,597)	(29,490)
Other comprehensive income before reclassifications	(1,174)	(99)
Amount reclassified from accumulated other comprehensive income	488	407
Other comprehensive income/(loss)	(686)	308
Balance at the End of the Period	(29,283)	(29,182)
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	(135)	(268)
Amount reclassified from accumulated other comprehensive income	68	75
Other comprehensive income/(loss)	(67)	(193)
Balance at the End of the Period	(246)	90
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	(1,041)	172
Other comprehensive income/(loss)	(1,041)	172
Balance at the End of the Period	(4,741)	(3,519)
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	3	(2)
Amount reclassified from accumulated other comprehensive income	419	333
Other comprehensive income/(loss)	422	330
Balance at the End of the Period	(24,296)	(25,753)
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)
Other comprehensive income/(loss)	0	(1)
Balance at the End of the Period	$ 0	$ (1)