Stock-Based Incentive Compensation Plans (Compensation Expense By Award Type) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based compensation arrangement by share-based payment award [Line Items]
Compensation expense	$ 62	$ 51	$ 50
Recognized tax benefit	13	11	18
Stock Options [Member]
Share-based compensation arrangement by share-based payment award [Line Items]
Compensation expense	8	5	10
Performance Shares [Member]
Share-based compensation arrangement by share-based payment award [Line Items]
Compensation expense	17	15	13
SARs [Member]
Share-based compensation arrangement by share-based payment award [Line Items]
Compensation expense		(1)	2
RSUs [Member]
Share-based compensation arrangement by share-based payment award [Line Items]
Compensation expense	$ 37	$ 32	$ 25