Share-Based Payments (Details 1) - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Jun. 30, 2017
Summary of share based compensation expense associated with different programs
Subtotal	$ 43.1	$ 53.9	$ 127.6	$ 158.4
Capitalized share-based compensation costs	(2.5)	(3.2)	(7.6)	(10.7)
Share-based compensation expense included in total costs and expenses	40.6	50.7	120.0	147.7
Market stock units
Summary of share based compensation expense associated with different programs
Share-based compensation expense	4.5	5.7	17.1	27.0
Time-vested restricted stock units
Summary of share based compensation expense associated with different programs
Share-based compensation expense	26.7	28.5	81.2	92.5
Cash settled performance shares
Summary of share based compensation expense associated with different programs
Share-based compensation expense	7.0	7.9	13.0	12.7
Performance units
Summary of share based compensation expense associated with different programs
Share-based compensation expense	3.2	9.1	8.9	17.3
Employee stock purchase plan
Summary of share based compensation expense associated with different programs
Share-based compensation expense	$ 1.7	$ 2.7	$ 7.4	$ 8.9
2017 Omnibus Equity Plan
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Shares of common stock available for grant under the 2017 Omnibus Equity Plan					8.0