Share-Based Payments (Details 1) - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Summary of share based compensation expense associated with different programs
Subtotal	$ 36.4	$ 50.2	$ 84.5	$ 104.5
Capitalized share-based compensation costs	(2.4)	(4.4)	(5.1)	(7.5)
Share-based compensation expense included in total costs and expenses	34.0	45.8	79.4	97.0
Market stock units
Summary of share based compensation expense associated with different programs
Share-based compensation expense	3.0	7.9	12.6	21.3
Time-vested restricted stock units
Summary of share based compensation expense associated with different programs
Share-based compensation expense	27.6	33.9	54.5	64.0
Cash settled performance shares
Summary of share based compensation expense associated with different programs
Share-based compensation expense	2.5	4.6	6.0	4.8
Performance units
Summary of share based compensation expense associated with different programs
Share-based compensation expense	1.2	1.3	5.7	8.2
Employee stock purchase plan
Summary of share based compensation expense associated with different programs
Share-based compensation expense	$ 2.1	$ 2.5	$ 5.7	$ 6.2
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		8.0