Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

Name:	us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Per basic share amount, after tax, of income (loss) from the day-to-day business activities of the discontinued operation.

+ References

No definition available.

Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Basic Earnings per Common Share
Income from continuing operations									$ 6,732	$ 8,084	$ 348
Less: cumulative dividends on subsidiary preferred stock									(151)	(98)	(16)
Income from continuing operations attributable to common stockholders									6,581	7,986	332
Loss from discontinued operations, net of tax									0	70	4,212
Net income (loss) attributable to common stockholders									$ 6,581	$ 7,916	$ (3,880)
Weighted-average common shares outstanding - basic (in shares)									1,424	1,411	1,465
Basic earnings per common share – continuing operations (in dollars per share)	$ (0.16)	$ 1.62	$ 1.68	$ 1.50	$ 1.42	$ 1.77	$ 1.68	$ 0.78	$ 4.62	$ 5.66	$ 0.23
Basic loss per common share – discontinued operations (in dollars per share)					0	0	0	0.05	0	0.05	2.88
Basic earnings (loss) per common share (in dollars per share)									$ 4.62	$ 5.61	$ (2.65)
Diluted earnings per share
Income from continuing operations attributable to common stockholders – diluted									$ 6,581	$ 7,986	$ 332
Loss from discontinued operations, net of tax – diluted									0	70	4,212
Net income (loss) attributable to common stockholders – diluted									$ 6,581	$ 7,916	$ (3,880)
Weighted-average common shares outstanding - basic (in shares)									1,424	1,411	1,465
Dilutive effect of warrants and awards under stock incentive plans (in shares)									15	20	27
Weighted-average common shares outstanding – diluted (in shares)									1,439	1,431	1,492
Diluted earnings per common share – continuing operations (in dollars per share)	$ (0.16)	$ 1.60	$ 1.66	$ 1.48	1.40	1.75	1.66	0.77	$ 4.57	$ 5.58	$ 0.22
Diluted loss per common share – discontinued operations (in dollars per share)					$ 0	$ 0	$ 0	$ 0.05	0	0.05	2.82
Diluted earnings (loss) per common share (in dollars per share)									$ 4.57	$ 5.53	$ (2.60)
Potentially dilutive securities (in shares)									7	9	0