Stock Compensation (Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended						1 Months Ended												3 Months Ended			6 Months Ended	12 Months Ended						1 Months Ended	12 Months Ended			1 Months Ended		12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 Long Term Incentive Plan [Member]	Dec. 31, 2012 Long Term Incentive Plan [Member]	Dec. 31, 2011 Long Term Incentive Plan [Member]	Nov. 30, 2013 Long Term Incentive Plan [Member] Class A [Member]	Aug. 31, 2013 Long Term Incentive Plan [Member] Class A [Member]	Jun. 30, 2013 Long Term Incentive Plan [Member] Class A [Member]	May 31, 2013 Long Term Incentive Plan [Member] Class A [Member] installment	Apr. 30, 2013 Long Term Incentive Plan [Member] Class A [Member]	Feb. 28, 2013 Long Term Incentive Plan [Member] Class A [Member]	Nov. 30, 2012 Long Term Incentive Plan [Member] Class A [Member]	Aug. 31, 2012 Long Term Incentive Plan [Member] Class A [Member]	May 31, 2012 Long Term Incentive Plan [Member] Class A [Member]	Jan. 31, 2012 Long Term Incentive Plan [Member] Class A [Member]	May 31, 2011 Long Term Incentive Plan [Member] Class A [Member]	Feb. 28, 2011 Long Term Incentive Plan [Member] Class A [Member]	Dec. 31, 2013 Long Term Incentive Plan [Member] Class A [Member] installment	Jun. 27, 2013 Long Term Incentive Plan [Member] Class A [Member] installment	Mar. 31, 2007 Long Term Incentive Plan [Member] Class A [Member]	Jun. 27, 2013 Long Term Incentive Plan [Member] Class A [Member] installment	Dec. 31, 2013 Long Term Incentive Plan [Member] Class A [Member]	Dec. 31, 2012 Long Term Incentive Plan [Member] Class A [Member]	Dec. 31, 2011 Long Term Incentive Plan [Member] Class A [Member]	Dec. 31, 2013 Long Term Incentive Plan [Member] Class B [Member]	Dec. 31, 2012 Long Term Incentive Plan [Member] Class B [Member]	Dec. 31, 2011 Long Term Incentive Plan [Member] Class B [Member]	Feb. 28, 2013 Short Term Incentive Plan [Member]	Dec. 31, 2013 Short Term Incentive Plan [Member]	Dec. 31, 2012 Short Term Incentive Plan [Member]	Dec. 31, 2011 Short Term Incentive Plan [Member]	Dec. 31, 2013 Director Stock Plan [Member]	May 31, 2013 Director Stock Plan [Member]	Dec. 31, 2013 Director Stock Plan [Member]	Dec. 31, 2012 Director Stock Plan [Member]	Dec. 31, 2011 Director Stock Plan [Member]	Dec. 31, 2013 Executive Incentive Plan [Member]	Dec. 31, 2012 Executive Incentive Plan [Member]	Dec. 31, 2011 Executive Incentive Plan [Member]	Dec. 31, 2012 UAW [Member] Class A [Member]	Dec. 31, 2011 UAW [Member] Class A [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	5 years
Company recognized total stock compensation expense, net of forfeitures	$ 19.6	$ 15.3	$ 11.2
Accelerated Vesting Expense	0.5
Employee Service Share-based Compensation, Tax Benefit from Compensation Expense	7.1	5.6	4.1
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized																																	3,000,000		3,000,000			12,000,000
Allocated Share-based Compensation Expense				0	0	0.1																	17.6	11.9	7.0					1.3	2.9	3.9			0.7	0.7		0	0	0.1
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Outstanding, Weighted Average Remaining Contractual Terms																																						1 year 6 months
Intrinsic value of the unvested				$ 80,300,000																										$ 2,100,000			$ 1,300,000		$ 1,300,000			$ 29,600,000
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition	2 months			3 years 2 months																															11 months
Number of shares granted							103,337	37,754	34,425	1,326,299	33,784	9,460	35,578	21,590	618,804	6,153	548,334	1,826	33,859	288,047	67,391								86,063	86,000	104,000	185,000	4,321	34,747	39,000	29,000	30,000				92,250	500
Grant Date Of Fair Value Of Shares Granted									0.7	27.6			1.1		15.3	0.1	12.9	0.1	1.0	6.0	2.0	0.8	4.0																		2.2	0.1
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period																																						10 years
Annual vesting installments, beginning on the one-year or two-year anniversary										3,000,000									3,000,000	3,000,000		3,000,000
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	0.1			22.7																													0.4		0.4
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Nonvested, beginning balance	2,700,000	2,600,000														1,558,000						1,704,000	1,704,000	1,558,000	1,490,000	0	0	28,000		96,000	171,000	0			29,000	27,000	33,000	880,000	880,000	1,366,000
Granted during period																							1,867,000	774,000	550,000	0	0	0
Vested during period																							(552,000)	(513,000)	(307,000)	0	0	(28,000)		(113,000)	(170,000)	(10,000)			(29,000)	(27,000)	(33,000)		0	(446,000)
Forfeited during period					0																		(661,000)	(115,000)	(175,000)	0		0		(7,000)	(9,000)	(4,000)				0	(3,000)	(11,000)	0	(40,000)
Nonvested, ending balance	3,400,000	2,700,000	2,600,000																2,358,000				2,358,000	1,704,000	1,558,000	0	0	0		62,000	96,000	171,000	39,000		39,000	29,000	27,000	869,000	880,000	880,000
Restricted Share Activity [Roll Forward]
Nonvested, beginning balance, value																32.0						38.3	38.3	32.0	27.6	0	0	0.8		2.3	4.3	0			0.7	0.6	0.7	9.8	9.8	15.4
Granted during period, value																							40.1	18.8	13.0	0	0	0		1.4	2.5	4.7			0.9	0.7	0.7
Vested during period, value																							(11.0)	(10.0)	(5.3)	0	0	(0.8)		(2.6)	(4.3)	(0.3)			(0.7)	(0.6)	(0.7)		0	(5.1)
Forfeited during period, value																							(15.1)	(2.5)	(3.3)	0	0	0		(0.1)	(0.2)	(0.1)				0	(0.1)		0	(0.5)
Nonvested, ending balance, value																			$ 52.3				$ 52.3	$ 38.3	$ 32.0	$ 0	$ 0	$ 0		$ 1.0	$ 2.3	$ 4.3	$ 0.9		$ 0.9	$ 0.7	$ 0.6	$ 9.8	$ 9.8	$ 9.8