Accumulated Other Comprehensive Income - Amounts Reclassified (Details) - USD ($) $ in Millions		3 Months Ended				6 Months Ended
		Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Other operating expenses		$ (606)		$ (684)		$ (1,385)	$ (1,624)
Interest expense		(259)		(355)		(512)	(603)
Income taxes		(81)		(101)		(174)	(334)
Discontinued operations, net of tax	[1]	(29)		(9)		(64)	1,179
NET INCOME		312	$ 320	299	$ 1,369	632	1,668
Reclassifications from AOCI | Gains & losses on cash flow hedges
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Income taxes		0		0		0	(1)
NET INCOME		0		2		1	3
Reclassifications from AOCI | Gains & losses on cash flow hedges | Commodity Contracts
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Other operating expenses		0		0		0	1
Reclassifications from AOCI | Gains & losses on cash flow hedges | Long-term debt
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Interest expense		0		2		1	3
Reclassifications from AOCI | Unrealized gains on AFS securities
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Discontinued operations, net of tax		0		0		0	(1)
Reclassifications from AOCI | Net prior service costs
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Other operating expenses		(7)		(19)		(14)	(37)
Income taxes		2		4		3	9
NET INCOME		$ (5)		$ (15)		$ (11)	$ (28)

[1] Net of income tax expense (benefits) of $39 million and $(16) million for the three months ended June 30, 2019 and 2018, respectively, and $44 million and $(887) million for the six months ended June 30, 2019 and 2018, respectively.