Share-Based Compensation Plans (Stock Option Activity) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Stock Options Outstanding, Beginning	2,040
Stock options, Granted	571
Stock options, Exercised	(521)
Stock options, Forfeited	(129)
Stock Options Outstanding, Ending	1,961	2,040
Options exercisable, Shares	1,227
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Weighted Average Exercise Price, Outstanding, Beginning	$ 48.56
Weighted Average Exercise Price / Share, Granted	74.60
Weighted Average Exercise Price / Share, Exercised	39.42
Weighted Average Exercise Price / Share, Forfeited	77.52
Weighted Average Exercise Price, Outstanding, Ending	56.66	$ 48.56
Options exercisable, Weighted Average Exercise Price	$ 46.29
Weighted Average Remaining Contractual Term, Outstanding	6 years 4 months 24 days	6 years 3 months 18 days
Aggregate intrinsic value of outstanding stock options	$ 89
Weighed average remaining contractual term, Options exercisable	4 years 10 months 24 days
Aggregate intrinsic value of exercisable stock options	$ 68
Vested and non-vested expected to vest as of December 31, 2020	1,896
Vested and non-vested expected to vest as of December 31, 2020	$ 56.08
Vested and non-vested expected to vest as of December 31, 2020	6 years 3 months 18 days
Aggregate intrinsic value, vested and expected to vest	$ 87