Accumulated Other Comprehensive Income (AOCI) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2016
Accumulated other comprehensive income (loss)
Balance of Accumulated Other Comprehensive Income (Loss) at Beginning of Period	$ (2,138)	$ (2,146)
Other comprehensive income (loss) before reclassifications	(110)	(109)
Amounts reclassified from AOCI	53	53
Other comprehensive income (loss), tax, portion attributable to parent	5	12
Other Comprehensive Income (Loss), Net of Tax	(52)	(44)
Balance of Accumulated Other Comprehensive Income (Loss) at End of period	(2,190)	(2,190)
Foreign Currency Translation Adjustment [Member]
Accumulated other comprehensive income (loss)
Balance of Accumulated Other Comprehensive Income (Loss) at Beginning of Period	(1,629)	(1,626)
Other comprehensive income (loss) before reclassifications	(39)	18
Amounts reclassified from AOCI	(2)	(75)
Other comprehensive income (loss), tax, portion attributable to parent	5	18
Other Comprehensive Income (Loss), Net of Tax	(36)	(39)
Balance of Accumulated Other Comprehensive Income (Loss) at End of period	(1,665)	(1,665)
Deferred Gain (Loss) On Hedging Activities [Member]
Accumulated other comprehensive income (loss)
Balance of Accumulated Other Comprehensive Income (Loss) at Beginning of Period	(26)	(15)
Other comprehensive income (loss) before reclassifications	(50)	(112)
Amounts reclassified from AOCI	51	102
Other comprehensive income (loss), tax, portion attributable to parent	3	3
Other Comprehensive Income (Loss), Net of Tax	4	(7)
Balance of Accumulated Other Comprehensive Income (Loss) at End of period	(22)	(22)
Pension Liability Adjustment [Member]
Accumulated other comprehensive income (loss)
Balance of Accumulated Other Comprehensive Income (Loss) at Beginning of Period	(510)	(523)
Other comprehensive income (loss) before reclassifications	1	(5)
Amounts reclassified from AOCI	10	32
Other comprehensive income (loss), tax, portion attributable to parent	(4)	(7)
Other Comprehensive Income (Loss), Net of Tax	7	20
Balance of Accumulated Other Comprehensive Income (Loss) at End of period	(503)	(503)
Unrealized Gain (Loss) On Investments [Member]
Accumulated other comprehensive income (loss)
Balance of Accumulated Other Comprehensive Income (Loss) at Beginning of Period	27	18
Other comprehensive income (loss) before reclassifications	(22)	(10)
Amounts reclassified from AOCI	(6)	(6)
Other comprehensive income (loss), tax, portion attributable to parent	1	(2)
Other Comprehensive Income (Loss), Net of Tax	(27)	(18)
Balance of Accumulated Other Comprehensive Income (Loss) at End of period	$ 0	$ 0