Retirement Plans and Other Retiree Benefits (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Pension Benefits, United States
Components of net periodic benefit cost
Service cost	$ 1	$ 1	$ 1	$ 1
Interest cost	26	25	53	50
ESOP offset	0	0	0	0
Expected return on plan assets	(28)	(29)	(55)	(58)
Amortization of transition and prior service costs (credits)	0	0	0	0
Amortization of actuarial loss (gain)	10	12	20	24
Net periodic benefit cost	9	9	19	17
Voluntary benefit plan contribution			50	0
Pension Benefits, International
Components of net periodic benefit cost
Service cost	4	5	8	10
Interest cost	6	7	12	15
ESOP offset	0	0	0	0
Expected return on plan assets	(6)	(6)	(11)	(14)
Amortization of transition and prior service costs (credits)	0	1	0	1
Amortization of actuarial loss (gain)	2	2	4	5
Net periodic benefit cost	6	9	13	17
Other Retiree Benefits
Components of net periodic benefit cost
Service cost	3	4	6	8
Interest cost	11	12	22	23
ESOP offset	(1)	(1)	(1)	(1)
Expected return on plan assets	0	0	0	(1)
Amortization of transition and prior service costs (credits)	0	0	0	0
Amortization of actuarial loss (gain)	4	7	8	14
Net periodic benefit cost	$ 17	$ 22	$ 35	$ 43