Employee Benefit Plans Employee Benefit Plans (Tables)

12 Months Ended

Dec. 31, 2017

Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract]

Schedule of Assumptions Used [Table Text Block]



	Pension Benefits												OPEB
	2017				2016				2015				2017		2016		2015
	U.S.		U.K.		U.S.		U.K.		U.S.		U.K.
Discount rate	3.65	%	2.75	%	4.15	%	2.70	%	4.40	%	3.90	%	3.65	%	4.20	%	4.45	%
Expected return on plan assets	7.45	%	5.10	%	7.50	%	5.00	%	7.50	%	5.00	%	N/A		N/A		N/A
Rate of compensation increase	4.00	%	3.40	%	4.00	%	3.45	%	4.00	%	3.30	%	4.00	%	4.00	%	4.00	%

Changes in Projected Benefit Obligations, Fair Value of Plan Assets, and Funded Status of Plan [Table Text Block]

The following table summarizes the changes in projected benefit obligations and plan assets and reconciles the funded status of the benefit plans, which is the net benefit plan liability:



	Pension Benefits						OPEB
	December 31,						December 31,
	2017			2016			2017			2016
	(in millions)
Change in benefit obligation
Benefit obligation at beginning of year	$	717.6		$	693.1		$	571.7		$	588.4
Service cost	3.6			2.9			0.3			0.3
Interest cost	28.9			28.8			13.3			14.0
Plan amendments	0.5			—			—			—
Actuarial loss (gain)	28.1			54.8			22.6			(6.8		)
Change in GM portion of OPEB obligation	—			—			16.5			(7.2		)
Participant contributions	0.3			0.3			—			—
Settlements	(14.3		)	—			—			—
Benefit payments	(40.8		)	(38.1		)	(12.5		)	(17.0		)
MPG acquisition / business combination	82.3			—			1.4			—
Currency fluctuations	17.8			(24.2		)	—			—
Net change	106.4			24.5			41.6			(16.7		)
Benefit obligation at end of year	$	824.0		$	717.6		$	613.3		$	571.7

Change in plan assets
Fair value of plan assets at beginning of year	$	611.3		$	612.8		$	—		$	—
Actual return on plan assets	74.9			61.7			—			—
Employer contributions	4.4			2.3			12.5			17.0
Participant contributions	0.3			0.3			—			—
Benefit payments	(40.8		)	(38.1		)	(12.5		)	(17.0		)
Settlements	(14.3		)	—			—			—
MPG acquisition / business combination	49.9			—			—			—
Currency fluctuations	16.5			(27.7		)	—			—
Net change	90.9			(1.5		)	—			—
Fair value of plan assets at end of year	$	702.2		$	611.3		$	—		$	—

Schedule of Amounts Recognized in Balance Sheet [Table Text Block]

Amounts recognized in our Consolidated Balance Sheets are as follows:



	Pension Benefits						OPEB
	December 31,						December 31,
	2017			2016			2017			2016
	(in millions)
Noncurrent assets	$	18.9		$	12.9		$	—		$	—
Current liabilities	(6.0		)	(5.7		)	(30.3		)	(29.1		)
Noncurrent liabilities	(134.7		)	(113.5		)	(583.0		)	(542.6		)
Net liability	$	(121.8	)	$	(106.3	)	$	(613.3	)	$	(571.7	)

Schedule of Pre-tax Amounts Recognized in Other Comprehensive Income (Loss) [Table Text Block]

Pre-tax amounts recorded in accumulated other comprehensive income (loss) (AOCI), not yet recognized in net periodic benefit cost (credit) as of December 31, 2017 and 2016, consists of:



	Pension Benefits						OPEB
	December 31,						December 31,
	2017			2016			2017			2016
	(in millions)
Net actuarial gain (loss)	$	(237.4	)	$	(247.9	)	$	(13.5	)	$	8.5
Net prior service credit (cost)	(0.1		)	0.5			7.2			9.9
Total amounts recorded	$	(237.5	)	$	(247.4	)	$	(6.3	)	$	18.4

Schedule of Net Benefit Costs [Table Text Block]

The components of net periodic benefit cost (credit) are as follows:



	Pension Benefits									OPEB
	2017			2016			2015			2017			2016			2015
	(in millions)
Service cost	$	3.6		$	2.9		$	3.2		$	0.3		$	0.3		$	0.4
Interest cost	28.9			28.8			28.6			13.3			14.0			15.0
Expected asset return	(44.0		)	(42.1		)	(42.0		)	—			—			—
Amortized actuarial loss	7.1			5.5			6.0			0.6			0.5			0.8
Amortized prior service credit	(0.1		)	(0.1		)	(0.1		)	(2.7		)	(2.7		)	(2.7		)
Settlement charge	3.2			—			—			—			—			—
Net periodic benefit cost (credit)	$	(1.3	)	$	(5.0	)	$	(4.3	)	$	11.5		$	12.1		$	13.5

Schedule of Allocation of Plan Assets [Table Text Block]



	U.S.					U.K.
					Target					Target
	2017		2016		Allocation	2017		2016		Allocation
Equity securities	42.7	%	42.0	%	30% - 65%	28.6	%	27.3	%	25% - 35%
Fixed income securities	47.5		48.0		35% - 55%	57.9		57.0		55% - 65%
Alternative assets	8.2		9.0		5% - 10%	11.2		11.7		5% - 15%
Cash	1.6		1.0		0% - 5%	2.3		4.0		0% - 5%
Total	100.0	%	100.0	%		100.0	%	100.0	%

The fair values of our pension plan assets are as follows:



December 31, 2017
Asset Categories	Level 1		Level 2		Level 3		Total
	(in millions)
Cash and Cash Equivalents	$	10.1	$	2.8	$	—	$	12.9
Equity
U.S. Large Cap	92.0		6.3		—		98.3
U.S. Small/Mid Cap	44.0		1.2		—		45.2
World Equity	123.5		6.2		—		129.7
Fixed Income Securities
Government & Agencies	81.3		46.4		—		127.7
Corporate Bonds - Investment Grade	150.5		4.2		—		154.7
Corporate Bonds - Non-investment Grade	24.8		1.8		—		26.6
Emerging Market Debt	25.2		1.2		—		26.4
Other	8.7		8.1		—		16.8
Other
Property Funds ^(a)	—		—		—		52.4
Liquid Alternatives Fund ^(a)	—		—		—		4.6
Structured Credit Fund ^(a)	—		—		—		6.0
Multi Strategy Hedge Fund ^(a)	—		—		—		0.9
Total Plan Assets	$	560.1	$	78.2	$	—	$	702.2

December 31, 2016
Asset Categories	Level 1		Level 2		Level 3		Total
	(in millions)
Cash and Cash Equivalents	$	10.4	$	—	$	—	$	10.4
Equity
U.S. Large Cap	90.9		—		—		90.9
U.S. Small/Mid Cap	37.3		—		—		37.3
World Equity	106.5		—		—		106.5
Fixed Income Securities
Government & Agencies	74.7		33.1		—		107.8
Corporate Bonds - Investment Grade	143.7		—		—		143.7
Corporate Bonds - Non-investment Grade	26.2		—		—		26.2
Emerging Market Debt	24.2		—		—		24.2
Other	5.0		—		—		5.0
Other
Property Funds ^(a)	—		—		—		45.5
Liquid Alternatives Fund ^(a)	—		—		—		—
Structured Credit Fund ^(a)	—		—		—		5.0
Multi Strategy Hedge Fund ^(a)	—		—		—		8.8
Total Plan Assets	$	518.9	$	33.1	$	—	$	611.3

(a) In accordance with Subtopic 820-10, certain investments that are measured at fair value using the net asset value per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the Consolidated Balance Sheets.