Employee Share-Based Incentive Compensation Plans (Details 4) (Non-Qualified Options, USD $) In Millions, except Share data, unless otherwise specified	1 Months Ended	3 Months Ended	6 Months Ended		1 Months Ended			1 Months Ended
	May 31, 2010	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	May 31, 2010 Before amendments	Jan. 31, 2007 Before amendments	May 26, 2010 Before amendments	May 31, 2010 Amended Grant	May 26, 2010 Amended Grant
Share-based compensation arrangement by share-based payment award
Stock-based awards, contractual term (in years)						7
Vesting period (in years)						5Y
Initial exercise price (in dollars per share)						$ 650.00
Fair value						$ 27.2	$ 3.5		$ 4.4
Amount amortized into income prior to the modification									18.2
Unamortized amount at modification date			0.9				9.0
Annual percentage increase in exercise price (as a percent)						5.00%
Assumptions of stock-based compensation awards
Expected volatility (as a percent)					41.00%	29.70%		34.00%
Risk-free rate (as a percent)					1.57%	1.10%		2.43%
Risk-free rate less the Escalator (as a percent)						4.70%
Forfeiture (as a percent)					0.00%	0.00%		0.00%
Expected dividend yield (as a percent)					0.32%	1.40%		0.32%
Expected life (in years)					3.67	7		6.67
Extension of contractual term (in years)								3
Exercise price (in dollar per share)									$ 742
Number of shares extinguished (in shares)									75,000
Threshold for in-the-money potential								100
Limit on value of in-the-money options over $100 million (as a percent)								50.00%
Expense recognized	8.7	9.7	0.1	11.1
Excess in the fair value of the amended grant over the original grant								$ 0.9
Granted (in shares)						200,000