Pension, Other Postretirement Benefits and Savings Plans - Changes in Fair Value of Plan Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
U.S.
Defined Benefit Plan Disclosure [Line Items]
Beginning balance	$ 6,250	$ 4,800
Foreign currency translation	0	0
Ending balance	5,011	6,250
U.S. | Commingled Funds
Defined Benefit Plan Disclosure [Line Items]
Beginning balance	0
Ending balance	0	0
U.S. | Real Estate
Defined Benefit Plan Disclosure [Line Items]
Beginning balance	0
Ending balance	0	0
U.S. | Asset Backed Securities
Defined Benefit Plan Disclosure [Line Items]
Beginning balance	123
Ending balance	158	123
U.S. | Significant Other Unobservable Inputs (Level 3) | Partnership Interests
Defined Benefit Plan Disclosure [Line Items]
Beginning balance	229	209
Realized gains (losses)	21	31
Unrealized (losses) gains relating to instruments still held at the reporting date	(12)	(15)
Purchases, sales, issuances and settlements (net)	(18)	4
Foreign currency translation	0	0
Ending balance	220	229
U.S. | Significant Other Unobservable Inputs (Level 3) | Other
Defined Benefit Plan Disclosure [Line Items]
Beginning balance	2	6
Realized gains (losses)	0	0
Unrealized (losses) gains relating to instruments still held at the reporting date	0	0
Purchases, sales, issuances and settlements (net)	0	(4)
Foreign currency translation	0	0
Ending balance	2	2
U.S. | Significant Other Unobservable Inputs (Level 3) | Commingled Funds
Defined Benefit Plan Disclosure [Line Items]
Beginning balance	0
Ending balance	0	0
U.S. | Significant Other Unobservable Inputs (Level 3) | Real Estate
Defined Benefit Plan Disclosure [Line Items]
Beginning balance	0
Ending balance	0	0
U.S. | Significant Other Unobservable Inputs (Level 3) | Asset Backed Securities
Defined Benefit Plan Disclosure [Line Items]
Beginning balance	0
Ending balance	0	0
Non-U.S.
Defined Benefit Plan Disclosure [Line Items]
Beginning balance	2,721	2,455
Foreign currency translation	(237)	(200)
Ending balance	2,493	2,721
Non-U.S. | Commingled Funds
Defined Benefit Plan Disclosure [Line Items]
Beginning balance	129
Ending balance	125	129
Non-U.S. | Real Estate
Defined Benefit Plan Disclosure [Line Items]
Beginning balance	136
Ending balance	143	136
Non-U.S. | Asset Backed Securities
Defined Benefit Plan Disclosure [Line Items]
Beginning balance	4
Ending balance	11	4
Non-U.S. | Significant Other Unobservable Inputs (Level 3) | Other
Defined Benefit Plan Disclosure [Line Items]
Beginning balance	21	19
Realized gains (losses)	0	0
Unrealized (losses) gains relating to instruments still held at the reporting date	0	0
Purchases, sales, issuances and settlements (net)	44	5
Foreign currency translation	(4)	(3)
Ending balance	61	21
Non-U.S. | Significant Other Unobservable Inputs (Level 3) | Commingled Funds
Defined Benefit Plan Disclosure [Line Items]
Beginning balance	122	163
Realized gains (losses)	0	1
Unrealized (losses) gains relating to instruments still held at the reporting date	2	7
Purchases, sales, issuances and settlements (net)	1	(42)
Foreign currency translation	(6)	(7)
Ending balance	119	122
Non-U.S. | Significant Other Unobservable Inputs (Level 3) | Real Estate
Defined Benefit Plan Disclosure [Line Items]
Beginning balance	134	170
Realized gains (losses)	0	1
Unrealized (losses) gains relating to instruments still held at the reporting date	12	18
Purchases, sales, issuances and settlements (net)	2	(47)
Foreign currency translation	(7)	(8)
Ending balance	141	134
Non-U.S. | Significant Other Unobservable Inputs (Level 3) | Asset Backed Securities
Defined Benefit Plan Disclosure [Line Items]
Beginning balance	0
Realized gains (losses)	0
Unrealized (losses) gains relating to instruments still held at the reporting date	0
Purchases, sales, issuances and settlements (net)	7
Foreign currency translation	0
Ending balance	$ 7	$ 0