Stock-Based Employee Compensation Plans (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Restricted Stock Units [Member]
Additional information with respect to restricted stock units and performance units [Abstract]
Number of Shares, Nonvested, January 1, 2011	3,159,265
Weighted Average Grant Date Fair Value on Number of Shares, Nonvested, January 1, 2011	$ 46.93
Number of Shares, Granted	866,646
Weighted Average Grant Date Fair Value on Number of Shares, Granted	$ 60.58	$ 51.04	$ 40.38
Number of Shares, Vested	(999,272)
Weighted Average Grant Date Fair Value on Number of Shares, Vested	$ 49.64
Number of Shares, Forfeited	(192,839)
Weighted Average Grant Date Fair Value on Number of Shares, Forfeited	$ 51.62
Number of Shares, Nonvested, December 31, 2011	2,833,800	3,159,265
Weighted Average Grant Date Fair Value on Number of Shares, Nonvested, December 31, 2011	$ 49.83	$ 46.93
Performance Units [Member]
Additional information with respect to restricted stock units and performance units [Abstract]
Number of Shares, Nonvested, January 1, 2011	1,384,230
Weighted Average Grant Date Fair Value on Number of Shares, Nonvested, January 1, 2011	$ 52.02
Number of Shares, Granted	525,459
Weighted Average Grant Date Fair Value on Number of Shares, Granted	$ 64.34	$ 60.06	$ 45.60
Number of Shares, Vested	(771,883)
Weighted Average Grant Date Fair Value on Number of Shares, Vested	$ 45.60
Number of Shares, Forfeited	(3,763)
Weighted Average Grant Date Fair Value on Number of Shares, Forfeited	$ 65.00
Number of Shares, Nonvested, December 31, 2011	1,134,043	1,384,230
Weighted Average Grant Date Fair Value on Number of Shares, Nonvested, December 31, 2011	$ 62.01	$ 52.02