Stock Based Incentive Compensation Plans (Summary of activity for stock options with service conditions) (Details) - Stock options with service conditions [Member] $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($) $ / shares shares
Shares
Outstanding as of beginning of year (in shares) | shares	2,354,016
Granted - original (in shares) | shares	678,882
Exercised (includes shares tendered) (in shares) | shares	(84,271)
Forfeited or expired (in shares) | shares	(53,971)
Outstanding as of end of year (in shares) | shares	2,894,656
Vested or expected to vest as of end of year (in shares) | shares	2,671,151	[1]
Exercisable as of end of year (in shares) | shares	1,865,223
Summary of activity for stock options, additional disclosures [Abstract]
Weighted average exercise price as of beginning of year (in dollars per share) | $ / shares	$ 53.11
Weighted average exercise price granted - original (in dollars per share) | $ / shares	63.01
Weighted average exercise price exercised (includes shares tendered) (in dollars per share) | $ / shares	33.32
Weighted average exercise price forfeited or expired (in dollars per share) | $ / shares	71.16
Weighted average exercise price outstanding as of end of year (in dollars per share) | $ / shares	55.67
Weighted average exercise price vested or expected to vest as of end of year (in dollars per share) | $ / shares	54.52	[1]
Weighted average exercise price exercisable as of end of year (in dollars per share) | $ / shares	$ 48.94
Weighted average remaining contractual term outstanding as of end of year (in years)	6 years 7 months 9 days
Weighted average remaining contractual term vested or expected to vest as of end of year (in years)	6 years 5 months 19 days	[1]
Weighted average remaining contractual term exercisable as of end of year (in years)	5 years 5 months 23 days
Aggregate intrinsic value outstanding as of end of year | $	$ 25
Aggregate intrinsic value vested or expected to vest as of end of year | $	25	[1]
Aggregate intrinsic value exercisable as of end of year | $	$ 25

[1] Includes estimated forfeitures.