Stock-Based Compensation Plans (Details 2) (USD $)	6 Months Ended
	Jun. 30, 2012
Restricted stock and Restricted stock units outstanding
Granted	$ 21.32
Vested, Shares	(52,417)
Equity Awards [Member]
Restricted stock and Restricted stock units outstanding
Beginning Balance, Shares	221,609
Beginning Balance, Weighted Average Grant Date Fair Value	$ 49.64
Granted	$ 63.37
Granted, Shares	359,732
Vested	$ 56.87
Vested, Shares	(85,294)
Forfeited	$ 57.56
Forfeited, Shares	(14,307)
Ending Balance, Shares	481,740
Ending Balance, Weighted Average Grant Date Fair Value	$ 58.37
Liability Awards [Member]
Restricted stock and Restricted stock units outstanding
Beginning Balance, Shares	487,244
Beginning Balance, Weighted Average Grant Date Fair Value	$ 48.76
Granted	$ 63.89
Granted, Shares	370,059
Vested	$ 50.51
Vested, Shares	(227,844)
Forfeited	$ 51.39
Forfeited, Shares	(1,717)
Ending Balance, Shares	627,742
Ending Balance, Weighted Average Grant Date Fair Value	$ 57.04