Retirement Benefits - Expense (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Other Assets	$ 7,490,000,000		$ 6,353,000,000
Other Liabilities and deferred revenue	41,644,000,000		43,577,000,000
Other Comprehensive Income/(Loss), Pension and Other Postretirement Benefit Plans, Adjustment, net of Tax	352,000,000	183,000,000
U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	147,000,000	127,000,000
Interest cost	454,000,000	498,000,000
Expected return on assets	(689,000,000)	(678,000,000)
Defined Benefit Plan Amortization Categories [Abstract]
Prior service costs/(credits)	39,000,000	39,000,000
(Gains)/Losses	116,000,000	51,000,000
Separation programs/other	2,000,000
(Gains)/Losses from curtailments	0	0
(Gains)/Losses from settlements	0
Total expense/(income)	69,000,000	37,000,000
Non-U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	135,000,000	118,000,000
Interest cost	239,000,000	300,000,000
Expected return on assets	(349,000,000)	(379,000,000)
Defined Benefit Plan Amortization Categories [Abstract]
Prior service costs/(credits)	12,000,000	14,000,000
(Gains)/Losses	205,000,000	148,000,000
Separation programs/other	7,000,000	16,000,000
(Gains)/Losses from curtailments	0	0
(Gains)/Losses from settlements	0	14,000,000
Total expense/(income)	249,000,000	231,000,000
Worldwide OPEB
Defined Benefit Plan Disclosure [Line Items]
Service cost	15,000,000	13,000,000
Interest cost	60,000,000	67,000,000
Expected return on assets	0	0
Defined Benefit Plan Amortization Categories [Abstract]
Prior service costs/(credits)	(51,000,000)	(57,000,000)
(Gains)/Losses	36,000,000	24,000,000
Separation programs/other	(1,000,000)	1,000,000
(Gains)/Losses from curtailments	0	0
(Gains)/Losses from settlements	0	0
Total expense/(income)	59,000,000	48,000,000
Plan Contributions [Abstract]
Defined Benefit Plan, Estimated Future Employer Contributions To Funded Plans in Current Fiscal Year	1,100,000,000
Pension And Other Postretirement Expected Benefit Contributions Unfunded Plans	400,000,000
Pension and Other Postretirement Benefit Contributions and Expected Future Employer Contributions To Funded and Unfunded Plans	1,500,000,000
Pension and Other Postretirement Benefit Contributions	800,000,000
Pension and Other Postretirement Benefit Contributions Unfunded Plans	100,000,000
2014 U.S. Pension Benefit Obligation Valuation Adjustment [Member]
Defined Benefit Plan Disclosure [Line Items]
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, before Tax	(782,000,000)
Other Assets	(301,000,000)
Other Liabilities and deferred revenue	481,000,000
Other Comprehensive Income/(Loss), Pension and Other Postretirement Benefit Plans, Adjustment, net of Tax	$ (508,000,000)