Stock Based Incentive Compensation Plans (Summary of activity for stock options with performance conditions) (Details) (Stock options with performance conditions [Member], USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014
Stock options with performance conditions [Member]
Summary of activity for stock options [Roll Forward]
Outstanding as of beginning of year (in shares)	1,176,974
Granted - original (in shares)	88,311
Exercised (includes shares tendered) (in shares)	(133,044)
Forfeited or expired (in shares)	(60,494)
Outstanding as of end of year (in shares)	1,071,747
Vested or expected to vest as of end of year (in shares)	1,016,926	[1]
Exercisable as of end of year (in shares)	962,105
Summary of activity for stock options, additional disclosures [Abstract]
Weighted average exercise price as of beginning of year (in dollars per share)	$ 45.84
Weighted average exercise price granted - original (in dollars per share)	$ 50.37
Weighted average exercise price exercised (includes shares tendered) (in dollars per share)	$ 34.14
Weighted average exercise price forfeited or expired (in dollars per share)	$ 40.46
Weighted average exercise price outstanding as of end of year (in dollars per share)	$ 47.93
Weighted average exercise price vested or expected to vest as of end of year (in dollars per share)	$ 48.31	[1]
Weighted average exercise price exercisable as of end of year (in dollars per share)	$ 48.73
Weighted average remaining contractual term outstanding as of end of year (in years)	2 years 11 months 16 days
Weighted average remaining contractual term vested or expected to vest as of end of year (in years)	2 years 11 months 5 days	[1]
Weighted average remaining contractual term exercisable as of end of year (in years)	2 years 10 months 24 days
Aggregate intrinsic value outstanding as of end of year	$ 10
Aggregate intrinsic value vested or expected to vest as of end of year	10	[1]
Aggregate intrinsic value exercisable as of end of year	$ 9

[1] Includes estimated forfeitures.