Debt (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Short-term Debt [Line Items]
Outstanding Balance	$ 1,878	$ 6,442
Short-term Debt [Member]
Short-term Debt [Line Items]
Year-End Stated Rate on Debt	0.61%	1.59%
Commercial Paper [Member]
Short-term Debt [Line Items]
Outstanding Balance	$ 0	$ 3,001
Commercial Paper [Member] | Short-term Debt [Member]
Short-term Debt [Line Items]
Year-End Stated Rate on Debt	0.00%	1.94%
Other Short Term Borrowings [Member]
Short-term Debt [Line Items]
Outstanding Balance	$ 1,878	$ 3,441
Other Short Term Borrowings [Member] | Short-term Debt [Member]
Short-term Debt [Line Items]
Year-End Stated Rate on Debt	0.61%	1.28%