Accumulated Other Comprehensive Income Reclassifications out of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total before tax		$ (1,238)	$ (1,536)	$ (2,496)	$ (3,208)
Tax (expense)/benefit		466	573	940	1,200
Net of tax		(772)	(963)	(1,556)	(2,008)
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]	0	(1)	0	(2)
Prior service credits	[1],[2]	1	0	1	1
Total before tax	[1]	1	(1)	1	(1)
Tax (expense)/benefit	[1]	(1)	1	(1)	1
Net of tax	[1]	$ 0	$ 0	$ 0	$ 0

[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 and retiree health and welfare cost (see Note 8 for additional details).