Employee Bargaining Agreements and Benefit Plans (Tables)

12 Months Ended

Dec. 31, 2017

Postemployment Benefits [Abstract]

Change in Benefit Obligation, Plan Assets and Funded Status of Defined Benefit Pension Plans

The change in benefit obligation, plan assets and the funded status of the defined benefit pension plans in the United Kingdom using a measurement date of December 31, 2017 and 2016, are as follows (in millions):

	Pension Benefits
At year end	2017			2016
Benefit obligation at beginning of year	$	13		$	16
Interest cost		—			1
Actuarial loss (gain)		1			3
Benefits paid		—			(1	)
Plan settlements		—			(3	)
Foreign currency exchange rate changes		(1	)		(3	)
Acquisitions (disposals)		—			—
Benefit obligation at end of year		13			13
Fair value of plan assets at beginning of year	$	15		$	18
Actual return		2			2
Benefits paid		—			(1	)
Company contributions		1			1
Plan settlements		—			(3	)
Foreign currency exchange rate changes		—			(2	)
Acquisitions (disposals)		—			—
Fair value of plan assets at end of year		18			15
Funded status		5			2
Accumulated benefit obligation at end of year		13			13

Assumption Rates Used for Benefit Obligations

The assumption rates used for benefit obligations are as follows:

	December 31,
	2017			2016
Discount rate:		2.50	%		2.70	%

Assumption Rates Used for Net Periodic Benefit Costs

The assumption rates used for net periodic benefit costs are as follows:

	December 31,
	2017	2016	2015
Discount rate:	2.70%	3.70%	3.10% - 3.90%
Expected return on assets:	3.27% - 4.27%	4.04% - 4.50%	2.13% - 5.50%

Plan's Assets Carried at Fair Value

The following table sets forth by level, within the fair value hierarchy, the Plan’s assets carried at fair value (in millions):

	Fair Value Measurements
	Total		Level 1		Level 2		Level 3
December 31, 2016:
Equity securities	$	8	$	8	$	—	$	—
Fixed Income Securities		3		3		—		—
Other		4		—		4		—
Total Fair Value Measurements	$	15	$	11	$	4	$	—
December 31, 2017:
Equity securities	$	10	$	10	$	—	$	—
Fixed Income Securities		3		3		—		—
Other		5		—		5		—
Total Fair Value Measurements	$	18	$	13	$	5	$	—