Income Taxes (Analysis of the Provision for Income Taxes) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
United States	$ 252	$ 215	$ 177
State	81	94	63
Other countries	298	238	229
Total	631	547	469
United States	62	50	16
State	5	(16)	22
Other countries	(22)	(5)	(36)
Total	45	29	2
Total provision for income taxes	$ 676	$ 576	$ 471