Accumulated Other Comprehensive Income (AOCI) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2017 USD ($)
Accumulated other comprehensive income (loss)
Balance of Accumulated Other Comprehensive Income (Loss) at Beginning of Period	$ (2,598)
Other comprehensive income (loss) before reclassifications	13
Amounts reclassified from AOCI	17
Other comprehensive income (loss), tax, portion attributable to parent	(6)
Other Comprehensive Income (Loss), Net of Tax	24
Balance of Accumulated Other Comprehensive Income (Loss) at End of period	(2,574)
Foreign Currency Translation Adjustment [Member]
Accumulated other comprehensive income (loss)
Balance of Accumulated Other Comprehensive Income (Loss) at Beginning of Period	(2,102)
Other comprehensive income (loss) before reclassifications	21
Amounts reclassified from AOCI	0
Other comprehensive income (loss), tax, portion attributable to parent	3
Other Comprehensive Income (Loss), Net of Tax	24
Balance of Accumulated Other Comprehensive Income (Loss) at End of period	(2,078)
Deferred Gain (Loss) On Hedging Activities [Member]
Accumulated other comprehensive income (loss)
Balance of Accumulated Other Comprehensive Income (Loss) at Beginning of Period	6
Other comprehensive income (loss) before reclassifications	1
Amounts reclassified from AOCI	2
Other comprehensive income (loss), tax, portion attributable to parent	(3)
Other Comprehensive Income (Loss), Net of Tax	0
Balance of Accumulated Other Comprehensive Income (Loss) at End of period	6
Pension Liability Adjustment [Member]
Accumulated other comprehensive income (loss)
Balance of Accumulated Other Comprehensive Income (Loss) at Beginning of Period	(521)
Other comprehensive income (loss) before reclassifications	(3)
Amounts reclassified from AOCI	15
Other comprehensive income (loss), tax, portion attributable to parent	(6)
Other Comprehensive Income (Loss), Net of Tax	6
Balance of Accumulated Other Comprehensive Income (Loss) at End of period	(515)
Unrealized Gain (Loss) On Investments [Member]
Accumulated other comprehensive income (loss)
Balance of Accumulated Other Comprehensive Income (Loss) at Beginning of Period	19
Other comprehensive income (loss) before reclassifications	(6)
Amounts reclassified from AOCI	0
Other comprehensive income (loss), tax, portion attributable to parent	0
Other Comprehensive Income (Loss), Net of Tax	(6)
Balance of Accumulated Other Comprehensive Income (Loss) at End of period	$ 13