Pensions and Other Employee Benefits, Net Loss and Prior Service Cost Balances in Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Net loss (gain)	$ 896	$ 768
Prior service cost (credit)	14	0
Total amount recognized	910	768
Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Net loss (gain)	(12)	(10)
Prior service cost (credit)	(4)	(3)
Total amount recognized	$ (16)	$ (13)