Share-based Compensation (Schedule of Stock Award Activity, Options, SARs & PSARs) (Details) - 6 months ended Jun. 30, 2015 - USD ($) $ / shares in Units, $ in Millions	Total
Employee Stock Option [Member] | Class A Ordinary Shares [Member]
Number of shares
Options outstanding at beginning of period (in shares)	1,726,259
Options granted (in shares)	61,763
Options cancelled/forfeited (in shares)	(13,836)
Options exercised (in shares)	(920,468)
Options outstanding at end of period (in shares)	853,718
Options exercisable at end of period (in shares)	417,692
Weighted average exercise price
Options outstanding at beginning of period (in dollars per shares)	$ 18.01
Options granted (in dollars per shares)	54.97
Options cancelled/forfeited (in dollars per share)	23.59
Options exercised (in dollars per shares)	14.03
Options outstanding at end of period (in dollars per shares)	24.90
Options exercisable at end of period (in dollars per shares)	$ 18.05
Weighted average remaining contractual term, in years
SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	5 years 7 months 6 days
Options exercisable at end of period	4 years 3 months 18 days
Total intrinsic value of awards exercised (in millions):
Options outstanding at end of period	$ 25.0
Options exercisable at end of period	$ 15.0
Employee Stock Option [Member] | Class C Ordinary Shares [Member]
Number of shares
Options outstanding at beginning of period (in shares)	3,946,192
Options granted (in shares)	622,301
Options cancelled/forfeited (in shares)	(34,493)
Options exercised (in shares)	(1,613,927)
Options outstanding at end of period (in shares)	2,920,073
Options exercisable at end of period (in shares)	1,377,436
Weighted average exercise price
Options outstanding at beginning of period (in dollars per shares)	$ 17.67
Options granted (in dollars per shares)	43.34
Options cancelled/forfeited (in dollars per share)	22.23
Options exercised (in dollars per shares)	14.99
Options outstanding at end of period (in dollars per shares)	24.57
Options exercisable at end of period (in dollars per shares)	$ 15.25
Weighted average remaining contractual term, in years
SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	6 years 1 month 6 days
Options exercisable at end of period	4 years 1 month 6 days
Total intrinsic value of awards exercised (in millions):
Options outstanding at end of period	$ 76.3
Options exercisable at end of period	$ 48.7
Stock Appreciation Rights (SARs) [Member] | Class A Ordinary Shares [Member]
Number of shares
Options outstanding at beginning of period (in shares)	5,607,988
Options granted (in shares)	2,252,602
Options cancelled/forfeited (in shares)	(106,696)
Options exercised (in shares)	(354,800)
Options outstanding at end of period (in shares)	7,399,094
Options exercisable at end of period (in shares)	2,815,909
Weighted average exercise price
Options outstanding at beginning of period (in dollars per shares)	$ 31.07
Options granted (in dollars per shares)	53.11
Options cancelled/forfeited (in dollars per share)	37.27
Options exercised (in dollars per shares)	25.68
Options outstanding at end of period (in dollars per shares)	37.95
Options exercisable at end of period (in dollars per shares)	$ 25.41
Weighted average remaining contractual term, in years
SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	5 years 1 month 6 days
Options exercisable at end of period	3 years 4 months 24 days
Total intrinsic value of awards exercised (in millions):
Options outstanding at end of period	$ 119.3
Options exercisable at end of period	$ 80.7
Stock Appreciation Rights (SARs) [Member] | Class C Ordinary Shares [Member]
Number of shares
Options outstanding at beginning of period (in shares)	14,689,045
Options granted (in shares)	4,505,204
Options cancelled/forfeited (in shares)	(262,502)
Options exercised (in shares)	(1,062,945)
Options outstanding at end of period (in shares)	17,868,802
Options exercisable at end of period (in shares)	7,907,213
Weighted average exercise price
Options outstanding at beginning of period (in dollars per shares)	$ 28.49
Options granted (in dollars per shares)	51.41
Options cancelled/forfeited (in dollars per share)	34.80
Options exercised (in dollars per shares)	23.48
Options outstanding at end of period (in dollars per shares)	34.47
Options exercisable at end of period (in dollars per shares)	$ 23.75
Weighted average remaining contractual term, in years
SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	4 years 9 months 18 days
Options exercisable at end of period	3 years 3 months 18 days
Total intrinsic value of awards exercised (in millions):
Options outstanding at end of period	$ 292.2
Options exercisable at end of period	$ 212.5
Performance Stock Appreciation Rights (PSARs) [Member] | Class A Ordinary Shares [Member]
Number of shares
Options outstanding at beginning of period (in shares)	2,788,749
Options cancelled/forfeited (in shares)	(35,625)
Options exercised (in shares)	(4,166)
Options outstanding at end of period (in shares)	2,748,958
Options exercisable at end of period (in shares)	7,708
Weighted average exercise price
Options outstanding at beginning of period (in dollars per shares)	$ 35.10
Options cancelled/forfeited (in dollars per share)	35.03
Options exercised (in dollars per shares)	35.03
Options outstanding at end of period (in dollars per shares)	35.10
Options exercisable at end of period (in dollars per shares)	$ 35.03
Weighted average remaining contractual term, in years
SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	5 years
Options exercisable at end of period	1 year 7 months 6 days
Total intrinsic value of awards exercised (in millions):
Options outstanding at end of period	$ 52.1
Options exercisable at end of period	$ 0.1
Performance Stock Appreciation Rights (PSARs) [Member] | Class C Ordinary Shares [Member]
Number of shares
Options outstanding at beginning of period (in shares)	8,366,248
Options cancelled/forfeited (in shares)	(106,875)
Options exercised (in shares)	(12,499)
Options outstanding at end of period (in shares)	8,246,874
Options exercisable at end of period (in shares)	23,124
Weighted average exercise price
Options outstanding at beginning of period (in dollars per shares)	$ 33.48
Options cancelled/forfeited (in dollars per share)	33.41
Options exercised (in dollars per shares)	33.41
Options outstanding at end of period (in dollars per shares)	33.48
Options exercisable at end of period (in dollars per shares)	$ 33.41
Weighted average remaining contractual term, in years
SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	5 years
Options exercisable at end of period	1 year 7 months 6 days
Total intrinsic value of awards exercised (in millions):
Options outstanding at end of period	$ 141.4
Options exercisable at end of period	$ 0.4