Income Taxes (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended							12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Current tax benefit (expense):
U.S. federal								$ 39.5	$ 52.4	$ (40.0)
State								(2.5)	(2.2)	(1.5)
Non-U.S.								5.1	(9.1)	(2.7)
Total current tax benefit (expense)								42.1	41.1	(44.2)
Deferred tax benefit (expense):
U.S. federal								(34.1)	(61.6)	(139.0)
Non-U.S.								114.7	3.6	(31.0)
Total deferred tax benefit (expense)								80.6	(58.0)	(170.0)
Total income tax benefit (expense)	$ 124.6	$ 0.6	$ (10.0)	$ 7.7	$ (6.6)	$ (11.7)	$ 1.4	$ 122.7	$ (16.9)	$ (214.2)