Fair Value of Other Instruments (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Obligations - Carrying Value	$ 17,752	$ 18,990
Debt Instrument, Fair Value Disclosure	18,666	19,036
Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Obligations - Carrying Value	17,736	18,276
Debt Instrument, Fair Value Disclosure	18,650	18,322
Commercial Paper Programs [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Obligations - Carrying Value		693
Debt Instrument, Fair Value Disclosure		693
Other Debt [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Obligations - Carrying Value	16	21
Debt Instrument, Fair Value Disclosure	$ 16	$ 21