Equity, Reclassification Out of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Gains (losses) reclassified out of accumulated other comprehensive income (loss)
Reclassification from accumulated other comprehensive income (loss), current period, net of tax		$ (19)	$ 0	$ (18)
Losses on cash flow hedges:
Total before tax		5,971	5,552	3,976
Tax (expense) benefit		(1,870)	(1,777)	(1,254)
Income from continuing operations		4,101	3,775	2,722
Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Component [Member]
Amortization of items related to defined benefit pension plans:
Reclassification from accumulated other comprehensive income (loss), current period, before tax	[1]	(62)	(34)	(57)
Reclassification from accumulated other comprehensive income (loss), current period, tax expense (benefit)		22	12	20
Gains (losses) reclassified out of accumulated other comprehensive income (loss)
Reclassification from accumulated other comprehensive income (loss), current period, net of tax		(40)	(22)	(37)
Accumulated Defined Benefit Plans Adjustment, Net Prior Service (Cost) Credit Component [Member]
Amortization of items related to defined benefit pension plans:
Reclassification from accumulated other comprehensive income (loss), current period, before tax	[1]	40	40	33
Reclassification from accumulated other comprehensive income (loss), current period, tax expense (benefit)		(14)	(14)	(12)
Gains (losses) reclassified out of accumulated other comprehensive income (loss)
Reclassification from accumulated other comprehensive income (loss), current period, net of tax		26	26	21
Accumulated Defined Benefit Plans Adjustment, Curtailment and Settlement Component [Member]
Amortization of items related to defined benefit pension plans:
Reclassification from accumulated other comprehensive income (loss), current period, before tax	[1]	(7)	(3)	(1)
Reclassification from accumulated other comprehensive income (loss), current period, tax expense (benefit)		2	0	0
Gains (losses) reclassified out of accumulated other comprehensive income (loss)
Reclassification from accumulated other comprehensive income (loss), current period, net of tax		(5)	(3)	(1)
Accumulated Defined Benefit Plans Adjustment [Member]
Amortization of items related to defined benefit pension plans:
Reclassification from accumulated other comprehensive income (loss), current period, before tax		(29)	3	(25)
Reclassification from accumulated other comprehensive income (loss), current period, tax expense (benefit)		10	(2)	8
Gains (losses) reclassified out of accumulated other comprehensive income (loss)
Reclassification from accumulated other comprehensive income (loss), current period, net of tax		(19)	1	(17)
Accumulated Net Gain (Loss) from Cash Flow Hedges [Member]
Amortization of items related to defined benefit pension plans:
Reclassification from accumulated other comprehensive income (loss), current period, before tax			(2)	(2)
Reclassification from accumulated other comprehensive income (loss), current period, tax expense (benefit)			1	1
Gains (losses) reclassified out of accumulated other comprehensive income (loss)
Reclassification from accumulated other comprehensive income (loss), current period, net of tax			(1)	(1)
Accumulated Net Gain (Loss) from Cash Flow Hedges [Member] | Reclassification out of Accumulated Other Comprehensive Income (Loss) [Member]
Losses on cash flow hedges:
Total before tax		0	(2)	(2)
Tax (expense) benefit		0	1	1
Income from continuing operations		0	(1)	(1)
Accumulated Net Gain (Loss) from Cash Flow Hedges [Member] | Reclassification out of Accumulated Other Comprehensive Income (Loss) [Member] | Commodity Contract [Member]
Losses on cash flow hedges:
Cost of sales		$ 0	$ (2)	$ (2)

[1] (a)These accumulated other comprehensive income (loss) components are included in the computation of net periodic benefit cost, as further discussed in Note 13. Net periodic benefit cost is reflected in operating expenses and general and administrative expenses.