Share-Based Compensation (Narrative) (Details)	12 Months Ended
	Dec. 31, 2014 USD ($) awards	Dec. 31, 2014 GBP (£)	Dec. 31, 2013 USD ($)	Dec. 31, 2012 USD ($)	Dec. 31, 2014 Minimum [Member]	Dec. 31, 2014 Maximum [Member]	May 31, 2011 Global Equity Incentive Plan, 2011 [Member]	May 31, 2010 Global Equity Incentive Plan, 2010 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Outstanding, Weighted Average Remaining Contractual Terms	1 year 2 months 22 days	1 year 2 months 22 days
Proportional vesting rate					0.00%	100.00%
Shares authorized under share awards plan							28,000,000	3,000,000
Share-based compensation expense	$ 138,000,000		$ 133,100,000	$ 136,400,000
Income tax benefit from share-based compensation agreements	39,100,000		37,800,000	39,100,000
Proceeds from Stock Options Exercised	11,000,000		17,900,000	23,000,000
Tax Benefit Realized From Share Based Payment Awards	7,400,000		7,900,000	5,400,000
Number of Share Awards By Type	2	2
Fair value of vested shares	202,300,000		192,700,000	151,600,000
Weighted average fair value of shares granted	$ 34.35		$ 26.91	$ 24.84
Unrecognized compensation cost related to non-vested shares	236,200,000
Weighted average non-vested shares compensation cost expected to recognize	2 years 6 months 25 days	2 years 6 months 25 days
Share options expiration date	10 years	10 years
Shares authorized under stock option plans, exercise price range, upper range limit		£ 8.86
Options, outstanding, weighted average remaining contractual term	11 months 25 days	11 months 25 days
Total intrinsic value of options exercised	22,900,000		28,500,000	19,600,000
Aggregate intrinsic value of options outstanding			7,000,000
Stock Price	39.52		36.40
ESPP discount rate	85.00%	85.00%
Maximum employee ESPP contributions per offering period	6,000
recognized expense for employee stock purchase	$ 800,000		$ 900,000	$ 300,000