Employee Retirement Benefits (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2015
U.S. Pension Plan
Components of Net Periodic Benefit Cost:
Service cost	$ 1	$ 6	$ 2	$ 14
Interest cost	7	8	14	16
Expected return on plan assets	(10)	(10)	(20)	(20)
Net amortizations	1	0	2	1
Settlement loss	1	4	2	4
Net periodic pension expense (benefit)	0	8	0	15
Non U.S. Pension Plan
Components of Net Periodic Benefit Cost:
Service cost	0	1	1	2
Interest cost	2	2	4	4
Expected return on plan assets	(4)	(4)	(8)	(8)
Net amortizations	1	0	1	0
Settlement loss	0	0	0	0
Net periodic pension expense (benefit)	(1)	(1)	(2)	(2)
Other disclosures
Contributions		$ 8		17
Non U.S. Pension Plan | United Kingdom
Other disclosures
Contributions	$ 0		$ 3
Employer discretionary contribution amount				$ 3
Forecast
Disclosure of net periodic benefit cost
Percent of match, first 3%					100.00%
Percent of match, remaining 2%					50.00%