Retirement Benefits - Changes in Level 3 Pension Benefit Plan Assets Measured at Fair Value on a Recurring Basis (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Fair Value Beginning Balance	$ 6,052	$ 6,359
Attributable to Assets Held at December 31	693	686
Attributable To Assets Sold	(8)	(44)
Net Purchases/(Settlements)	(592)	(770)
Transfers into / (out of) Level 3, net	(19)	(179)
Fair Value Ending Balance	6,126	6,052
U.S. Plans | Equity
Defined Benefit Plan Disclosure [Line Items]
Fair Value Beginning Balance	4	18
Attributable to Assets Held at December 31	0	0
Attributable To Assets Sold	(4)	0
Net Purchases/(Settlements)	0	(2)
Transfers into / (out of) Level 3, net	0	(12)
Fair Value Ending Balance	0	4
U.S. Plans | U.S. companies
Defined Benefit Plan Disclosure [Line Items]
Fair Value Beginning Balance	3	15
Attributable to Assets Held at December 31	0	0
Attributable To Assets Sold	(3)	0
Net Purchases/(Settlements)	0	0
Transfers into / (out of) Level 3, net	0	(12)
Fair Value Ending Balance	0	3
U.S. Plans | International companies
Defined Benefit Plan Disclosure [Line Items]
Fair Value Beginning Balance	1	3
Attributable to Assets Held at December 31	0	0
Attributable To Assets Sold	(1)	0
Net Purchases/(Settlements)	0	(2)
Transfers into / (out of) Level 3, net	0	0
Fair Value Ending Balance	0	1
U.S. Plans | Fixed Income
Defined Benefit Plan Disclosure [Line Items]
Fair Value Beginning Balance	33	294
Attributable to Assets Held at December 31	0	0
Attributable To Assets Sold	0	(6)
Net Purchases/(Settlements)	34	(92)
Transfers into / (out of) Level 3, net	(19)	(163)
Fair Value Ending Balance	48	33
U.S. Plans | U.S. government-sponsored enterprises
Defined Benefit Plan Disclosure [Line Items]
Fair Value Beginning Balance		3
Attributable to Assets Held at December 31		0
Attributable To Assets Sold		0
Net Purchases/(Settlements)		0
Transfers into / (out of) Level 3, net		(3)
Fair Value Ending Balance		0
U.S. Plans | Non-U.S. government
Defined Benefit Plan Disclosure [Line Items]
Fair Value Beginning Balance		32
Attributable to Assets Held at December 31		0
Attributable To Assets Sold		(1)
Net Purchases/(Settlements)		(28)
Transfers into / (out of) Level 3, net		(3)
Fair Value Ending Balance		0
U.S. Plans | Investment grade
Defined Benefit Plan Disclosure [Line Items]
Fair Value Beginning Balance		80
Attributable to Assets Held at December 31		0
Attributable To Assets Sold		(4)
Net Purchases/(Settlements)		(33)
Transfers into / (out of) Level 3, net		(43)
Fair Value Ending Balance		0
U.S. Plans | High yield
Defined Benefit Plan Disclosure [Line Items]
Fair Value Beginning Balance		14
Attributable to Assets Held at December 31		0
Attributable To Assets Sold		(1)
Net Purchases/(Settlements)		(12)
Transfers into / (out of) Level 3, net		(1)
Fair Value Ending Balance		0
U.S. Plans | Other credit
Defined Benefit Plan Disclosure [Line Items]
Fair Value Beginning Balance	0	50
Attributable to Assets Held at December 31	0	0
Attributable To Assets Sold	0	(7)
Net Purchases/(Settlements)	0	(26)
Transfers into / (out of) Level 3, net	14	(17)
Fair Value Ending Balance	14	0
U.S. Plans | Mortgage/other asset-backed
Defined Benefit Plan Disclosure [Line Items]
Fair Value Beginning Balance	33	115
Attributable to Assets Held at December 31	0	0
Attributable To Assets Sold	0	7
Net Purchases/(Settlements)	34	7
Transfers into / (out of) Level 3, net	(33)	(96)
Fair Value Ending Balance	34	33
U.S. Plans | Alternatives
Defined Benefit Plan Disclosure [Line Items]
Fair Value Beginning Balance	6,014	5,990
Attributable to Assets Held at December 31	693	685
Attributable To Assets Sold	(4)	(40)
Net Purchases/(Settlements)	(625)	(621)
Transfers into / (out of) Level 3, net	0	0
Fair Value Ending Balance	6,078	6,014
U.S. Plans | Hedge funds
Defined Benefit Plan Disclosure [Line Items]
Fair Value Beginning Balance	2,778	3,121
Attributable to Assets Held at December 31	205	295
Attributable To Assets Sold	(4)	(40)
Net Purchases/(Settlements)	(504)	(598)
Transfers into / (out of) Level 3, net	0	0
Fair Value Ending Balance	2,475	2,778
U.S. Plans | Private equity
Defined Benefit Plan Disclosure [Line Items]
Fair Value Beginning Balance	2,626	2,412
Attributable to Assets Held at December 31	403	345
Attributable To Assets Sold	0	0
Net Purchases/(Settlements)	(247)	(131)
Transfers into / (out of) Level 3, net	0	0
Fair Value Ending Balance	2,782	2,626
U.S. Plans | Real estate
Defined Benefit Plan Disclosure [Line Items]
Fair Value Beginning Balance	610	457
Attributable to Assets Held at December 31	85	45
Attributable To Assets Sold	0	0
Net Purchases/(Settlements)	126	108
Transfers into / (out of) Level 3, net	0	0
Fair Value Ending Balance	821	610
U.S. Plans | Other
Defined Benefit Plan Disclosure [Line Items]
Fair Value Beginning Balance	1	57
Attributable to Assets Held at December 31	0	1
Attributable To Assets Sold	0	2
Net Purchases/(Settlements)	(1)	(55)
Transfers into / (out of) Level 3, net	0	(4)
Fair Value Ending Balance	0	1
Foreign Pension Plan, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value Beginning Balance	7,980	6,475
Attributable to Assets Held at December 31	284	710
Attributable To Assets Sold	(291)	11
Net Purchases/(Settlements)	(167)	796
Transfers into / (out of) Level 3, net	(116)	(12)
Fair Value Ending Balance	7,690	7,980
Foreign Pension Plan, Defined Benefit [Member] | Equity
Defined Benefit Plan Disclosure [Line Items]
Fair Value Beginning Balance	2	1
Attributable to Assets Held at December 31	0	0
Attributable To Assets Sold	(1)	0
Net Purchases/(Settlements)	(1)	0
Transfers into / (out of) Level 3, net	0	1
Fair Value Ending Balance	0	2
Foreign Pension Plan, Defined Benefit [Member] | International companies
Defined Benefit Plan Disclosure [Line Items]
Fair Value Beginning Balance	2	1
Attributable to Assets Held at December 31	0	0
Attributable To Assets Sold	(1)	0
Net Purchases/(Settlements)	(1)	0
Transfers into / (out of) Level 3, net	0	1
Fair Value Ending Balance	0	2
Foreign Pension Plan, Defined Benefit [Member] | Fixed Income
Defined Benefit Plan Disclosure [Line Items]
Fair Value Beginning Balance	170	97
Attributable to Assets Held at December 31	0	(8)
Attributable To Assets Sold	1	1
Net Purchases/(Settlements)	(55)	93
Transfers into / (out of) Level 3, net	(116)	(13)
Fair Value Ending Balance	0	170
Foreign Pension Plan, Defined Benefit [Member] | Non-U.S. government
Defined Benefit Plan Disclosure [Line Items]
Fair Value Beginning Balance	67	41
Attributable to Assets Held at December 31	0	(7)
Attributable To Assets Sold	(2)	0
Net Purchases/(Settlements)	(12)	33
Transfers into / (out of) Level 3, net	(53)	0
Fair Value Ending Balance	0	67
Foreign Pension Plan, Defined Benefit [Member] | Investment grade
Defined Benefit Plan Disclosure [Line Items]
Fair Value Beginning Balance	55	22
Attributable to Assets Held at December 31	0	(1)
Attributable To Assets Sold	3	(1)
Net Purchases/(Settlements)	(17)	32
Transfers into / (out of) Level 3, net	(41)	3
Fair Value Ending Balance	0	55
Foreign Pension Plan, Defined Benefit [Member] | High yield
Defined Benefit Plan Disclosure [Line Items]
Fair Value Beginning Balance	21	1
Attributable to Assets Held at December 31	0	0
Attributable To Assets Sold	0	0
Net Purchases/(Settlements)	(15)	19
Transfers into / (out of) Level 3, net	(6)	1
Fair Value Ending Balance	0	21
Foreign Pension Plan, Defined Benefit [Member] | Other credit
Defined Benefit Plan Disclosure [Line Items]
Fair Value Beginning Balance	13	6
Attributable to Assets Held at December 31	0	0
Attributable To Assets Sold	0	0
Net Purchases/(Settlements)	(7)	7
Transfers into / (out of) Level 3, net	(6)	0
Fair Value Ending Balance	0	13
Foreign Pension Plan, Defined Benefit [Member] | Mortgage/other asset-backed
Defined Benefit Plan Disclosure [Line Items]
Fair Value Beginning Balance	14	28
Attributable to Assets Held at December 31	0	0
Attributable To Assets Sold	0	2
Net Purchases/(Settlements)	(4)	1
Transfers into / (out of) Level 3, net	(10)	(17)
Fair Value Ending Balance	0	14
Foreign Pension Plan, Defined Benefit [Member] | Fixed Income Funds Net Derivative Financial Instruments [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value Beginning Balance		(1)
Attributable to Assets Held at December 31		0
Attributable To Assets Sold		0
Net Purchases/(Settlements)		1
Transfers into / (out of) Level 3, net		0
Fair Value Ending Balance		0
Foreign Pension Plan, Defined Benefit [Member] | Alternatives
Defined Benefit Plan Disclosure [Line Items]
Fair Value Beginning Balance	2,610	1,707
Attributable to Assets Held at December 31	284	190
Attributable To Assets Sold	(9)	10
Net Purchases/(Settlements)	80	703
Transfers into / (out of) Level 3, net	0	0
Fair Value Ending Balance	2,965	2,610
Foreign Pension Plan, Defined Benefit [Member] | Hedge funds
Defined Benefit Plan Disclosure [Line Items]
Fair Value Beginning Balance	1,657	1,142
Attributable to Assets Held at December 31	169	114
Attributable To Assets Sold	5	10
Net Purchases/(Settlements)	(82)	391
Transfers into / (out of) Level 3, net	0	0
Fair Value Ending Balance	1,749	1,657
Foreign Pension Plan, Defined Benefit [Member] | Private equity
Defined Benefit Plan Disclosure [Line Items]
Fair Value Beginning Balance	352	236
Attributable to Assets Held at December 31	63	34
Attributable To Assets Sold	0	0
Net Purchases/(Settlements)	123	82
Transfers into / (out of) Level 3, net	0	0
Fair Value Ending Balance	538	352
Foreign Pension Plan, Defined Benefit [Member] | Real estate
Defined Benefit Plan Disclosure [Line Items]
Fair Value Beginning Balance	601	329
Attributable to Assets Held at December 31	52	42
Attributable To Assets Sold	(14)	0
Net Purchases/(Settlements)	39	230
Transfers into / (out of) Level 3, net	0	0
Fair Value Ending Balance	678	601
Foreign Pension Plan, Defined Benefit [Member] | Other
Defined Benefit Plan Disclosure [Line Items]
Fair Value Beginning Balance	5,198	4,670
Attributable to Assets Held at December 31	0	528
Attributable To Assets Sold	(282)	0
Net Purchases/(Settlements)	(191)	0
Transfers into / (out of) Level 3, net	0	0
Fair Value Ending Balance	4,725	5,198
Foreign Pension Plan, Defined Benefit [Member] | Other Pension Benefit Plan Asset Insurance Contracts [Member] | Ford Werke GmbH [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value Ending Balance	$ 3,800	$ 4,100