Reclassifications out of Accumulated Other Comprehensive Income (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total before tax	$ (1,672)		$ (1,169)
Tax (expense)/benefit	(627)		(445)
Net of tax	(1,045)		(724)
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)	[1],[2]	(1)	[1],[2]
Prior service credits	1	[1],[2]	1	[1],[2]
Total before tax	0		0
Tax (expense)/benefit	0		0
Net of tax	$ 0		$ 0

[1] 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).

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