Reclassifications Out of Accumulated Other Comprehensive Income (Loss) - Components of AOCI (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
RECLASSIFICATIONS OUT OF ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)
At beginning of period			$ 13,089
Other comprehensive income (loss)	$ 51	$ (68)	89	$ (128)
At end of period	14,569	13,099	14,569	13,099
Accumulated Other Comprehensive (Loss) Income
RECLASSIFICATIONS OUT OF ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)
At beginning of period			(478)	(182)
Change in other comprehensive income (loss) before reclassifications			(66)
Reclassifications from accumulated other comprehensive income (loss)			155
Other comprehensive income (loss)			89	(128)
At end of period	(389)	(310)	(389)	(310)
Marketable securities adjustments
RECLASSIFICATIONS OUT OF ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)
At beginning of period			(142)
Change in other comprehensive income (loss) before reclassifications			(44)
Reclassifications from accumulated other comprehensive income (loss)			100
Other comprehensive income (loss)			56
At end of period	(86)		(86)
Foreign currency translation adjustments
RECLASSIFICATIONS OUT OF ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)
At beginning of period			127
Change in other comprehensive income (loss) before reclassifications			(8)
Other comprehensive income (loss)			(8)
At end of period	119		119
Pension and other post-retirement benefit adjustments
RECLASSIFICATIONS OUT OF ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)
At beginning of period			(249)
Change in other comprehensive income (loss) before reclassifications			30
Reclassifications from accumulated other comprehensive income (loss)	5	$ 2	15	$ 7
Other comprehensive income (loss)			45
At end of period	(204)		(204)
Changes in fair value of cash flow hedge instruments
RECLASSIFICATIONS OUT OF ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)
At beginning of period			(214)
Change in other comprehensive income (loss) before reclassifications			(44)
Reclassifications from accumulated other comprehensive income (loss)			40
Other comprehensive income (loss)			(4)
At end of period	$ (218)		$ (218)