Share-Based Payments (Details 1) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Summary of share based compensation expense associated with different programs
Subtotal	$ 43.1	$ 36.1	$ 91.6	$ 74.4
Share-based compensation expense included in total costs and expenses	41.8	35.1	89.1	72.4
Capitalized share-based compensation costs	(1.3)	(1.0)	(2.5)	(2.0)
Stock Options [Member]
Summary of share based compensation expense associated with different programs
Share-based compensation expense	0.8	1.6	0.9	2.7
Market stock units [Member]
Summary of share based compensation expense associated with different programs
Share-based compensation expense	5.6	4.3	11.6	7.7
Time-vested restricted stock units [Member]
Summary of share based compensation expense associated with different programs
Share-based compensation expense	22.2	19.1	48.1	46.2
Performance-vested restricted stock units settled in shares [Member]
Summary of share based compensation expense associated with different programs
Share-based compensation expense		0.3	0.1	0.7
Cash settled performance shares [Member]
Summary of share based compensation expense associated with different programs
Share-based compensation expense	13.9	10.7	28.7	15.5
Employee stock purchase plan [Member]
Summary of share based compensation expense associated with different programs
Share-based compensation expense	$ 0.6	$ 0.1	$ 2.2	$ 1.6