Accumulated Other Comprehensive Income (AOCI) (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2020
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance of Accumulated Other Comprehensive Income (Loss) at Beginning of Period	$ (2,764)	$ (2,405)
Other comprehensive income (loss) before reclassifications	(17)	(378)
Amounts reclassified from AOCI	62	106
Other comprehensive income (loss), tax, portion attributable to parent	14	(28)
Other Comprehensive Income (Loss), Net of Tax	59	(300)
Balance of Accumulated Other Comprehensive Income (Loss) at End of period	(2,705)	(2,705)
Foreign Currency Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance of Accumulated Other Comprehensive Income (Loss) at Beginning of Period	(2,439)	(2,152)
Other comprehensive income (loss) before reclassifications	(34)	(279)
Amounts reclassified from AOCI	0	0
Other comprehensive income (loss), tax, portion attributable to parent	28	(14)
Other Comprehensive Income (Loss), Net of Tax	(6)	(293)
Balance of Accumulated Other Comprehensive Income (Loss) at End of period	(2,445)	(2,445)
Deferred Gain (Loss) On Hedging Activities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance of Accumulated Other Comprehensive Income (Loss) at Beginning of Period	(80)	(12)
Other comprehensive income (loss) before reclassifications	24	(102)
Amounts reclassified from AOCI	57	101
Other comprehensive income (loss), tax, portion attributable to parent	(15)	(1)
Other Comprehensive Income (Loss), Net of Tax	66	(2)
Balance of Accumulated Other Comprehensive Income (Loss) at End of period	(14)	(14)
Pension Liability Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance of Accumulated Other Comprehensive Income (Loss) at Beginning of Period	(276)	(268)
Other comprehensive income (loss) before reclassifications	(4)	0
Amounts reclassified from AOCI	5	5
Other comprehensive income (loss), tax, portion attributable to parent	0	(12)
Other Comprehensive Income (Loss), Net of Tax	1	(7)
Balance of Accumulated Other Comprehensive Income (Loss) at End of period	(275)	(275)
Unrealized Gain (Loss) On Investments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance of Accumulated Other Comprehensive Income (Loss) at Beginning of Period	31	27
Other comprehensive income (loss) before reclassifications	(3)	3
Amounts reclassified from AOCI	0	0
Other comprehensive income (loss), tax, portion attributable to parent	1	(1)
Other Comprehensive Income (Loss), Net of Tax	(2)	2
Balance of Accumulated Other Comprehensive Income (Loss) at End of period	$ 29	$ 29