Pension and Other Postretirement Employee Benefit Plans - Plan Assets and Liabilities Measured At Fair Value (Details) - USD ($)	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined benefit pension plans
Pension and OPEB plan assets and liabilities - supplemental information
Unfunded commitments to purchase limited partnership investments for the plan	$ 895,000,000	$ 1,200,000,000
Excluded amount of US receivables for investments sold and dividends and interest receivables	74,000,000	106,000,000
Excluded amount of other liabilities	17,000,000	16,000,000
U.S. defined benefit pension plans
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	14,125,000,000	14,623,000,000	$ 14,354,000,000
Pension and OPEB plan assets and liabilities - supplemental information
Excluded amount of payables for investments purchased	106,000,000	241,000,000
U.S. defined benefit pension plans | Level 3
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	539,000,000	351,000,000	441,000,000	$ 425,000,000
U.S. defined benefit pension plans | Total assets measured at fair value
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	10,139,000,000	10,466,000,000
U.S. defined benefit pension plans | Total assets measured at fair value | Level 1
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	7,670,000,000	8,266,000,000
U.S. defined benefit pension plans | Total assets measured at fair value | Level 2
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	1,930,000,000	1,849,000,000
U.S. defined benefit pension plans | Total assets measured at fair value | Level 3
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	539,000,000	351,000,000
U.S. defined benefit pension plans | Cash and cash equivalents
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	112,000,000	87,000,000
U.S. defined benefit pension plans | Cash and cash equivalents | Level 1
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	112,000,000	87,000,000
U.S. defined benefit pension plans | Cash and cash equivalents | Level 2
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	0	0
U.S. defined benefit pension plans | Cash and cash equivalents | Level 3
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	0	0
U.S. defined benefit pension plans | Equity securities
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	4,833,000,000	5,310,000,000
U.S. defined benefit pension plans | Equity securities | Level 1
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	4,826,000,000	5,286,000,000
U.S. defined benefit pension plans | Equity securities | Level 2
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	5,000,000	20,000,000
U.S. defined benefit pension plans | Equity securities | Level 3
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	2,000,000	4,000,000	4,000,000	4,000,000
U.S. defined benefit pension plans | Common/collective trust funds
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	339,000,000	345,000,000
U.S. defined benefit pension plans | Common/collective trust funds | Level 1
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	339,000,000	345,000,000
U.S. defined benefit pension plans | Common/collective trust funds | Level 2
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	0	0
U.S. defined benefit pension plans | Common/collective trust funds | Level 3
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	0	0
U.S. defined benefit pension plans | Limited partnerships
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	53,000,000	70,000,000
U.S. defined benefit pension plans | Limited partnerships | Level 1
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	53,000,000	70,000,000
U.S. defined benefit pension plans | Limited partnerships | Level 2
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	0	0
U.S. defined benefit pension plans | Limited partnerships | Level 3
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	0	0
U.S. defined benefit pension plans | Corporate debt securities
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	1,621,000,000	1,463,000,000
U.S. defined benefit pension plans | Corporate debt securities | Level 1
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	0	0
U.S. defined benefit pension plans | Corporate debt securities | Level 2
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	1,619,000,000	1,454,000,000
U.S. defined benefit pension plans | Corporate debt securities | Level 3
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	2,000,000	9,000,000	7,000,000	1,000,000
U.S. defined benefit pension plans | U.S. federal, state, local and non-U.S. government debt securities
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	688,000,000	607,000,000
U.S. defined benefit pension plans | U.S. federal, state, local and non-U.S. government debt securities | Level 1
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	580,000,000	446,000,000
U.S. defined benefit pension plans | U.S. federal, state, local and non-U.S. government debt securities | Level 2
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	108,000,000	161,000,000
U.S. defined benefit pension plans | U.S. federal, state, local and non-U.S. government debt securities | Level 3
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	0	0
U.S. defined benefit pension plans | Mortgage-backed securities
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	68,000,000	75,000,000
U.S. defined benefit pension plans | Mortgage-backed securities | Level 1
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	0	1,000,000
U.S. defined benefit pension plans | Mortgage-backed securities | Level 2
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	67,000,000	73,000,000
U.S. defined benefit pension plans | Mortgage-backed securities | Level 3
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	1,000,000	1,000,000	0	0
U.S. defined benefit pension plans | Derivative receivables
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	104,000,000	114,000,000
U.S. defined benefit pension plans | Derivative receivables | Level 1
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	0	0
U.S. defined benefit pension plans | Derivative receivables | Level 2
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	104,000,000	114,000,000
U.S. defined benefit pension plans | Derivative receivables | Level 3
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	0	0
U.S. defined benefit pension plans | Other
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	2,321,000,000	2,395,000,000
U.S. defined benefit pension plans | Other | Level 1
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	1,760,000,000	2,031,000,000
U.S. defined benefit pension plans | Other | Level 2
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	27,000,000	27,000,000
U.S. defined benefit pension plans | Other | Level 3
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	534,000,000	337,000,000	430,000,000	420,000,000
U.S. defined benefit pension plans | Certain limited partnerships and common/collective trust funds
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	4,100,000,000	4,300,000,000
U.S. defined benefit pension plans | Certain limited partnerships and common/collective trust funds | Level 2
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	1,300,000,000
U.S. defined benefit pension plans | Certain limited partnerships and common/collective trust funds | Level 3
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value		3,000,000,000
U.S. defined benefit pension plans | Total liabilities measured at fair value
Pension and OPEB plan assets and liabilities measured at fair value
Plan liabilities measured at fair value	(35,000,000)	(23,000,000)
U.S. defined benefit pension plans | Total liabilities measured at fair value | Level 1
Pension and OPEB plan assets and liabilities measured at fair value
Plan liabilities measured at fair value	0	0
U.S. defined benefit pension plans | Total liabilities measured at fair value | Level 2
Pension and OPEB plan assets and liabilities measured at fair value
Plan liabilities measured at fair value	(35,000,000)	(23,000,000)
U.S. defined benefit pension plans | Total liabilities measured at fair value | Level 3
Pension and OPEB plan assets and liabilities measured at fair value
Plan liabilities measured at fair value	0	0
U.S. defined benefit pension plans | Derivative payables
Pension and OPEB plan assets and liabilities measured at fair value
Plan liabilities measured at fair value	(35,000,000)	(23,000,000)
U.S. defined benefit pension plans | Derivative payables | Level 1
Pension and OPEB plan assets and liabilities measured at fair value
Plan liabilities measured at fair value	0	0
U.S. defined benefit pension plans | Derivative payables | Level 2
Pension and OPEB plan assets and liabilities measured at fair value
Plan liabilities measured at fair value	(35,000,000)	(23,000,000)
U.S. defined benefit pension plans | Derivative payables | Level 3
Pension and OPEB plan assets and liabilities measured at fair value
Plan liabilities measured at fair value	0	0
Non-U.S. defined benefit pension plans
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	3,511,000,000	3,718,000,000	3,532,000,000
Non-U.S. defined benefit pension plans | Level 3
Pension and OPEB plan assets and liabilities - supplemental information
Fair value of plan assets and liabilities	0	0
Non-U.S. defined benefit pension plans | Total assets measured at fair value
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	3,430,000,000	3,606,000,000
Non-U.S. defined benefit pension plans | Total assets measured at fair value | Level 1
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	1,722,000,000	1,779,000,000
Non-U.S. defined benefit pension plans | Total assets measured at fair value | Level 2
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	1,708,000,000	1,827,000,000
Non-U.S. defined benefit pension plans | Cash and cash equivalents
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	115,000,000	129,000,000
Non-U.S. defined benefit pension plans | Cash and cash equivalents | Level 1
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	114,000,000	128,000,000
Non-U.S. defined benefit pension plans | Cash and cash equivalents | Level 2
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	1,000,000	1,000,000
Non-U.S. defined benefit pension plans | Equity securities
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	1,159,000,000	1,188,000,000
Non-U.S. defined benefit pension plans | Equity securities | Level 1
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	1,002,000,000	1,019,000,000
Non-U.S. defined benefit pension plans | Equity securities | Level 2
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	157,000,000	169,000,000
Non-U.S. defined benefit pension plans | Common/collective trust funds
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	135,000,000	112,000,000
Non-U.S. defined benefit pension plans | Common/collective trust funds | Level 1
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	135,000,000	112,000,000
Non-U.S. defined benefit pension plans | Common/collective trust funds | Level 2
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	0	0
Non-U.S. defined benefit pension plans | Limited partnerships
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	0	0
Non-U.S. defined benefit pension plans | Limited partnerships | Level 1
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	0	0
Non-U.S. defined benefit pension plans | Limited partnerships | Level 2
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	0	0
Non-U.S. defined benefit pension plans | Corporate debt securities
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	758,000,000	724,000,000
Non-U.S. defined benefit pension plans | Corporate debt securities | Level 1
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	0	0
Non-U.S. defined benefit pension plans | Corporate debt securities | Level 2
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	758,000,000	724,000,000
Non-U.S. defined benefit pension plans | U.S. federal, state, local and non-U.S. government debt securities
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	716,000,000	775,000,000
Non-U.S. defined benefit pension plans | U.S. federal, state, local and non-U.S. government debt securities | Level 1
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	212,000,000	235,000,000
Non-U.S. defined benefit pension plans | U.S. federal, state, local and non-U.S. government debt securities | Level 2
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	504,000,000	540,000,000
Non-U.S. defined benefit pension plans | Mortgage-backed securities
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	28,000,000	79,000,000
Non-U.S. defined benefit pension plans | Mortgage-backed securities | Level 1
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	2,000,000	2,000,000
Non-U.S. defined benefit pension plans | Mortgage-backed securities | Level 2
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	26,000,000	77,000,000
Non-U.S. defined benefit pension plans | Derivative receivables
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	209,000,000	258,000,000
Non-U.S. defined benefit pension plans | Derivative receivables | Level 1
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	0	0
Non-U.S. defined benefit pension plans | Derivative receivables | Level 2
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	209,000,000	258,000,000
Non-U.S. defined benefit pension plans | Other
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	310,000,000	341,000,000
Non-U.S. defined benefit pension plans | Other | Level 1
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	257,000,000	283,000,000
Non-U.S. defined benefit pension plans | Other | Level 2
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	53,000,000	58,000,000
Non-U.S. defined benefit pension plans | Certain limited partnerships and common/collective trust funds
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	234,000,000	251,000,000
Non-U.S. defined benefit pension plans | Certain limited partnerships and common/collective trust funds | Level 3
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value		251,000,000
Non-U.S. defined benefit pension plans | Total liabilities measured at fair value
Pension and OPEB plan assets and liabilities measured at fair value
Plan liabilities measured at fair value	(153,000,000)	(139,000,000)
Non-U.S. defined benefit pension plans | Total liabilities measured at fair value | Level 1
Pension and OPEB plan assets and liabilities measured at fair value
Plan liabilities measured at fair value	0	0
Non-U.S. defined benefit pension plans | Total liabilities measured at fair value | Level 2
Pension and OPEB plan assets and liabilities measured at fair value
Plan liabilities measured at fair value	(153,000,000)	(139,000,000)
Non-U.S. defined benefit pension plans | Derivative payables
Pension and OPEB plan assets and liabilities measured at fair value
Plan liabilities measured at fair value	(153,000,000)	(139,000,000)
Non-U.S. defined benefit pension plans | Derivative payables | Level 1
Pension and OPEB plan assets and liabilities measured at fair value
Plan liabilities measured at fair value	0	0
Non-U.S. defined benefit pension plans | Derivative payables | Level 2
Pension and OPEB plan assets and liabilities measured at fair value
Plan liabilities measured at fair value	(153,000,000)	(139,000,000)
OPEB plans
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	1,855,000,000	1,903,000,000	1,757,000,000
OPEB plans | Level 3
Pension and OPEB plan assets and liabilities measured at fair value
Plan assets measured at fair value	$ 1,855,000,000	$ 1,903,000,000	$ 1,749,000,000	$ 1,554,000,000