Income Taxes (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Pretax income (loss)
U.S.									$ 580.1	$ 273.5	$ 462.6
International									(60.6)	0.5	14.0
Total pretax income (loss)	89.3	112.0	234.8	83.4	60.2	47.5	83.1	83.2	519.5	274.0	476.6
Current
Federal									167.9	69.6	99.0
State and local									25.7	10.4	23.4
International									12.9	9.4	10.3
Total current									206.5	89.4	132.7
Deferred
Federal									(3.2)	11.0	32.5
State and local									(4.7)	0.4	(0.4)
International									(3.1)	(5.0)	(5.7)
Total deferred									(11.0)	6.4	26.4
Total provision for income taxes	51.4	26.1	89.9	28.1	23.0	14.0	28.7	30.1	195.5	95.8	159.1
Differences between the Company's effective income tax rate and the U.S. federal income tax statutory rate
Provision for income taxes using the statutory rate in effect									181.8	95.9	166.7
Tax effect of:
State and local income taxes, net									6.6	7.0	13.9
International income taxes, net									26.1	2.7	(2.2)
Earnings of U.S. unconsolidated affiliates									(2.9)	(2.8)	(4.1)
Valuation allowance									3.0	1.8	0.4
Tax credits									(20.3)	(10.5)	(10.0)
Uncertain tax positions									15.0	7.7	1.5
Dividend received deduction									(3.0)	(2.2)	(8.2)
Domestic production activities deduction									(9.7)	(6.9)
Other									(1.1)	3.1	1.1
Total provision for income taxes	$ 51.4	$ 26.1	$ 89.9	$ 28.1	$ 23.0	$ 14.0	$ 28.7	$ 30.1	$ 195.5	$ 95.8	$ 159.1
Effective income tax rate (as a percent)									37.60%	35.00%	33.40%
Statutory federal income tax rate (as a percent)									35.00%	35.00%	35.00%