Stock Compensation Plans (Details 2) (USD $)	3 Months Ended
	Mar. 31, 2012 Y	Mar. 31, 2011 Y
Weighted-Average Exercise Price
Weighted average remaining contractual life of stock options outstanding (in years)	3.1	3.8
Stock Options
Weighted Average assumptions, weighted average expected life and estimated fair value of options
Weighted average volatility (as a percent)	0.00%	26.10%
Expected dividend yield (as a percent)	0.00%	1.30%
Risk-free rate (as a percent)	0.00%	2.20%
Weighted average expected life (in years)	0.0	5.5
Weighted average estimated fair value per share	$ 0.00	$ 10.92
Stock Options
Outstanding at beginning of period (in shares)	9,116,000	13,919,000
Granted (in shares)		80,000
Exercised (in shares)	(1,032,000)	(2,344,000)
Forfeited and expired (in shares)	(12,000)	(127,000)
Outstanding at end of period (in shares)	8,072,000	11,528,000
Exercisable at end of period (in shares)	7,173,000	9,461,000
Weighted-Average Exercise Price
Outstanding at beginning of period (in dollars per share)	$ 32	$ 32
Granted (in dollars per share)		$ 53
Exercised (in dollars per share)	$ 35	$ 33
Forfeited and expired (in dollars per share)	$ 40	$ 37
Outstanding at end of period (in dollars per share)	$ 31	$ 32
Exercisable at end of period (in dollars per share)	$ 30	$ 30
Incentive compensation plans | Stock Options
Stock Options
Granted (in shares)		80,000
Weighted-Average Exercise Price
Granted (in dollars per share)		$ 53