Fair Value Measurements Fair Value, Assets and Liabilities Measured on Recurring Basis (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, Assets	$ 2	$ 14
Derivatives, Liabilities	(441)	(118)
Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds	3,658	2,562
Commercial Paper, at Carrying Value	67	108
Available for sale debt instruments	159	242
Available for Sale Securities, Government Agencies		55
Investments, Fair Value Disclosure	35	33
Derivatives, Assets	2	14
Total assets	3,921	3,014
Derivatives, Liabilities	(441)	(118)
Total liabilities	(441)	(118)
Fair Value, Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds	3,658	2,562
Available for Sale Securities, Government Agencies		55
Available-for-sale Securities, Equity Securities	35	33
Total assets	3,693	2,650
Fair Value, Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commercial Paper, at Carrying Value	67	108
Available for sale debt instruments	159	242
Derivatives, Assets	2	14
Total assets	228	364
Derivatives, Liabilities	(441)	(118)
Total liabilities	$ (441)	$ (118)