Reclassifications out of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total before tax		$ (1,839)	$ (1,654)	$ (5,047)	$ (4,295)
Tax (expense)/benefit		683	619	1,883	1,620
Net of tax		(1,156)	(1,035)	(3,164)	(2,675)
Accumulated Defined Benefit Plans Adjustment [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Actuarial losses	[1],[2]	(1)	0	(3)	(1)
Prior service credits	[1],[2]	1	1	2	2
Total before tax		0	1	(1)	1
Tax (expense)/benefit		0	0	1	0
Net of tax		$ 0	$ 1	$ 0	$ 1

[1] Amounts in parenthesis indicate debits to the income statement.

[2] This accumulated other comprehensive income component is included in the computation of net periodic pension cost and retiree health and welfare (see Note 8 for additional details).