Equity Activity - AOCI Rollforward (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Accumulated Other Comprehensive Income (Loss) (net of tax)
Balance at the Beginning of the Period	$ 18,392	$ 14,424
Other comprehensive income/(loss)	688	608
Balance at the End of the Period	18,448	15,072
Accumulated Other Comprehensive Income/(Loss)
Accumulated Other Comprehensive Income (Loss) (net of tax)
Balance at the Beginning of the Period	(29,398)	(29,607)
Other comprehensive income before reclassifications	284	218
Amount reclassified from accumulated other comprehensive income	404	391
Other comprehensive income/(loss)	688	608
Balance at the End of the Period	(28,710)	(28,998)
Net Unrealized Gains/(Losses) on Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss) (net of tax)
Balance at the Beginning of the Period	319	100
Other comprehensive income before reclassifications	(25)	(174)
Amount reclassified from accumulated other comprehensive income	(64)	(58)
Other comprehensive income/(loss)	(89)	(232)
Balance at the End of the Period	230	(133)
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) (net of tax)
Balance at the Beginning of the Period	(3,603)	(3,463)
Other comprehensive income before reclassifications	270	505
Amount reclassified from accumulated other comprehensive income	0	0
Other comprehensive income/(loss)	270	505
Balance at the End of the Period	(3,333)	(2,958)
Net Change Retirement-Related Benefit Plans
Accumulated Other Comprehensive Income (Loss) (net of tax)
Balance at the Beginning of the Period	(26,116)	(26,248)
Other comprehensive income before reclassifications	40	(91)
Amount reclassified from accumulated other comprehensive income	466	426
Other comprehensive income/(loss)	507	335
Balance at the End of the Period	(25,609)	(25,913)
Net Unrealized Gains/(Losses) on Available-For-Sale Securities
Accumulated Other Comprehensive Income (Loss) (net of tax)
Balance at the Beginning of the Period	2	5
Other comprehensive income before reclassifications	(1)	(22)
Amount reclassified from accumulated other comprehensive income	1	23
Other comprehensive income/(loss)	0	0
Balance at the End of the Period	$ 2	$ 5