Long-term and Short-term Debt (Short-term with Maturities of Year or Less) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Debt Disclosure [Abstract]
Commercial paper	$ 99	$ 99
Other Short-term Borrowings	136	169
Short-term Debt	235	268
Average daily balance	$ 216	$ 429
Average days outstanding	34 days	32 days