Reporting Segments and Related Information (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
Segment Reporting Information [Line Items]
Net sales	$ 1,719.1		$ 1,695.2	$ 1,856.4	$ 1,912.5	$ 1,773.7		$ 1,791.8	$ 1,818.8	$ 1,730.4	$ 7,183.2		$ 7,114.7		$ 5,652.8
Inter-segment sales											0		0		0
Net sales by reportable segment											7,183.2		7,114.7		5,652.8
Year-end assets	6,400.8					5,958.6					6,400.8		5,958.6		5,555.0
Depreciation and amortization											288.6		283.0		252.9
Long-lived asset expenditures											407.4	[1]	393.7	[1]	276.6	[1]
Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales											7,183.2		7,114.7		5,652.8
Inter-segment sales											0		0		0
Net sales by reportable segment											7,183.2		7,114.7		5,652.8
Year-end assets	4,951.4					4,891.8					4,951.4		4,891.8		4,508.2
Depreciation and amortization											269.1		268.6		248.0
Long-lived asset expenditures											395.5	[1]	380.2	[1]	264.8	[1]
Engine [Member]
Segment Reporting Information [Line Items]
Net sales											4,884.5		5,030.2		4,041.4
Inter-segment sales											28.5		20.4		19.4
Net sales by reportable segment											4,913.0		5,050.6		4,060.8
Year-end assets	3,299.2					3,329.0					3,299.2		3,329.0		3,277.7
Depreciation and amortization											177.8		188.6		184.4
Long-lived asset expenditures											269.9	[1]	264.3	[1]	181.3	[1]
Drivetrain [Member]
Segment Reporting Information [Line Items]
Net sales											2,298.7		2,084.5		1,611.4
Inter-segment sales											0		0		0
Net sales by reportable segment											2,298.7		2,084.5		1,611.4
Year-end assets	1,652.2					1,562.8					1,652.2		1,562.8		1,230.5
Depreciation and amortization											91.3		80.0		63.6
Long-lived asset expenditures											125.6	[1]	115.9	[1]	83.5	[1]
Inter-segment eliminations [Member]
Segment Reporting Information [Line Items]
Net sales											0		0		0
Inter-segment sales											(28.5)		(20.4)		(19.4)
Net sales by reportable segment											(28.5)		(20.4)		(19.4)
Year-end assets	0					0					0		0		0
Depreciation and amortization											0		0		0
Long-lived asset expenditures											0	[1]	0	[1]	0	[1]
Corporate [Member]
Segment Reporting Information [Line Items]
Net sales											0	[2]	0	[2]	0	[2]
Inter-segment sales											0	[2]	0	[2]	0	[2]
Net sales by reportable segment											0	[2]	0	[2]	0	[2]
Year-end assets	1,449.4	[2]				1,066.8	[2]				1,449.4	[2]	1,066.8	[2]	1,046.8	[2]
Depreciation and amortization											19.5	[2]	14.4	[2]	4.9	[2]
Long-lived asset expenditures											$ 11.9	[1],[2]	$ 13.5	[1],[2]	$ 11.8	[1],[2]

[1] Long-lived asset expenditures include capital expenditures and tooling outlays.

[2] Corporate assets include investments and advances and deferred income taxes.