Equity Activity - AOCI Rollforward (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Accumulated Other Comprehensive Income (Loss) (net of tax)
Balance at the Beginning of the Period	$ 16,607	$ 18,290	$ 16,929	$ 17,725
Other comprehensive income/(loss)	340	294	649	724
Balance at the End of the Period	17,776	18,648	17,776	18,648
Common stock repurchase authorization available, value	2,123		2,123
Accumulated Other Comprehensive Income/(Loss)
Accumulated Other Comprehensive Income (Loss) (net of tax)
Balance at the Beginning of the Period	(29,182)	(28,583)	(29,490)	(26,592)
Other comprehensive income before reclassifications			29	(617)
Amount reclassified from accumulated other comprehensive income			620	1,340
Other comprehensive income/(loss)	340	294	649	724
Balance at the End of the Period	(28,841)	(28,290)	(28,841)	(28,290)
Accumulated Other Comprehensive Income/(Loss) | Accounting Standards Updates 2016-01 (Financial Instruments), 2017-12 (Hedging) and 2018-02 (Stranded Tax Effects)
Accumulated Other Comprehensive Income (Loss) (net of tax)
Cumulative Effect Of Prospective Application Of New Accounting Principle, Net Of Tax				(2,422)
Net Unrealized Gains/(Losses) on Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss) (net of tax)
Balance at the Beginning of the Period			284	35
Other comprehensive income before reclassifications	(4)	(111)	(272)	(60)
Amount reclassified from accumulated other comprehensive income			(51)	284
Other comprehensive income/(loss)	(129)	214	(323)	224
Balance at the End of the Period	(39)	264	(39)	264
Net Unrealized Gains/(Losses) on Cash Flow Hedges | Accounting Standards Updates 2016-01 (Financial Instruments), 2017-12 (Hedging) and 2018-02 (Stranded Tax Effects)
Accumulated Other Comprehensive Income (Loss) (net of tax)
Cumulative Effect Of Prospective Application Of New Accounting Principle, Net Of Tax				5
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) (net of tax)
Balance at the Beginning of the Period			(3,690)	(2,834)
Other comprehensive income before reclassifications			214	(620)
Other comprehensive income/(loss)	42	(505)	214	(620)
Balance at the End of the Period	(3,477)	(3,408)	(3,477)	(3,408)
Foreign Currency Translation Adjustments | Accounting Standards Updates 2016-01 (Financial Instruments), 2017-12 (Hedging) and 2018-02 (Stranded Tax Effects)
Accumulated Other Comprehensive Income (Loss) (net of tax)
Cumulative Effect Of Prospective Application Of New Accounting Principle, Net Of Tax				46
Net Change Retirement-Related Benefit Plans
Accumulated Other Comprehensive Income (Loss) (net of tax)
Balance at the Beginning of the Period			(26,083)	(23,796)
Other comprehensive income before reclassifications			89	64
Amount reclassified from accumulated other comprehensive income			671	1,057
Other comprehensive income/(loss)	430	584	760	1,121
Balance at the End of the Period	(25,323)	(25,146)	(25,323)	(25,146)
Net Change Retirement-Related Benefit Plans | Accounting Standards Updates 2016-01 (Financial Instruments), 2017-12 (Hedging) and 2018-02 (Stranded Tax Effects)
Accumulated Other Comprehensive Income (Loss) (net of tax)
Cumulative Effect Of Prospective Application Of New Accounting Principle, Net Of Tax				(2,471)
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	3
Other comprehensive income before reclassifications	(1)	0	(2)	(1)
Other comprehensive income/(loss)	(1)	0	(2)	(1)
Balance at the End of the Period	$ (2)	$ 0	$ (2)	0
Net Unrealized Gains/(Losses) on Available-For-Sale Securities | Accounting Standards Updates 2016-01 (Financial Instruments), 2017-12 (Hedging) and 2018-02 (Stranded Tax Effects)
Accumulated Other Comprehensive Income (Loss) (net of tax)
Cumulative Effect Of Prospective Application Of New Accounting Principle, Net Of Tax				$ (2)