Retirement Plans and Other Retiree Benefits (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Pension Benefits, United States
Components of net periodic benefit cost
Service cost	$ 0	$ 0	$ 1	$ 1
Interest cost	27	25	80	75
ESOP offset	0	0	0	0
Expected return on plan assets	(27)	(29)	(82)	(87)
Amortization of transition and prior service costs (credits)	0	0	0	0
Amortization of actuarial loss (gain)	10	12	30	36
Net periodic benefit cost	10	8	29	25
Voluntary benefit plan contribution			53	0
Pension Benefits, International
Components of net periodic benefit cost
Service cost	4	4	12	14
Interest cost	7	6	19	21
ESOP offset	0	0	0	0
Expected return on plan assets	(6)	(6)	(17)	(20)
Amortization of transition and prior service costs (credits)	0	1	0	2
Amortization of actuarial loss (gain)	2	3	6	8
Net periodic benefit cost	7	8	20	25
Other Retiree Benefits
Components of net periodic benefit cost
Service cost	4	5	10	13
Interest cost	10	11	32	34
ESOP offset	0	0	(1)	(1)
Expected return on plan assets	0	(1)	0	(2)
Amortization of transition and prior service costs (credits)	0	0	0	0
Amortization of actuarial loss (gain)	3	6	11	20
Net periodic benefit cost	$ 17	$ 21	$ 52	$ 64