Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation.

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Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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Amount after tax of increase (decrease) to equity or (increase) decrease to net assets, resulting from the cumulative effect adjustment of a new accounting principle applied in the period of adoption.

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Amount of paid and unpaid common stock dividends declared with the form of settlement in cash, stock and payment-in-kind (PIK).

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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Amount after tax and reclassification adjustments of other comprehensive income (loss).

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Number, before forfeiture, of shares issued under share-based payment arrangement. Excludes employee stock ownership plan (ESOP).

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Value, before forfeiture, of shares issued under share-based payment arrangement. Excludes employee stock ownership plan (ESOP).

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Equity impact of the cost of common and preferred stock that were repurchased during the period. Recorded using the cost method.

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CONSOLIDATED STATEMENTS OF EQUITY - USD ($) $ in Millions	Total	Common shares [Member]	Additional paid-in capital [Member]	Retained earnings [Member]	Treasury shares [Member]	AOCI Attributable to Parent [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of change in accounting policy	$ 0
Cumulative effect of change in accounting policy \| Cumulative effect of adoption of equity securities guidance	(1)			$ 1		$ (1)
Beginning balance (in shares) at Dec. 31, 2017		146,634,664
Beginning balance at Dec. 31, 2017	5,995	$ 3	$ 8,085	11,326	$ (13,648)	229
Comprehensive income (loss) [Abstract]
Net income	1,559			1,559
Other comprehensive income (loss), net of tax	(472)					(472)
Total comprehensive income	1,087
Dividends to shareholders	(388)			(388)
Repurchase of common shares (in shares)		(8,526,715)
Repurchase of common shares	(1,265)				(1,265)
Share-based compensation plans (in shares)		1,711,676
Share-based compensation plans	189		129		60
Ending balance (in shares) at Sep. 30, 2018		139,819,625
Ending balance at Sep. 30, 2018	5,618	$ 3	8,214	12,498	(14,853)	(244)
Beginning balance (in shares) at Jun. 30, 2018		142,220,411
Beginning balance at Jun. 30, 2018	5,632	$ 3	8,171	12,126	(14,489)	(179)
Comprehensive income (loss) [Abstract]
Net income	503			503
Other comprehensive income (loss), net of tax	(65)					(65)
Total comprehensive income	438
Dividends to shareholders	(131)			(131)
Repurchase of common shares (in shares)		(2,548,686)
Repurchase of common shares	(365)				(365)
Share-based compensation plans (in shares)		147,900
Share-based compensation plans	44		43		1
Ending balance (in shares) at Sep. 30, 2018		139,819,625
Ending balance at Sep. 30, 2018	5,618	$ 3	8,214	12,498	(14,853)	(244)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of change in accounting policy	(5)
Cumulative effect of change in accounting policy \| Cumulative effect of adoption of premium amort on purchased callable debt				(5)
Beginning balance (in shares) at Dec. 31, 2018		136,330,747
Beginning balance at Dec. 31, 2018	5,588	$ 3	8,260	12,909	(15,293)	(291)
Comprehensive income (loss) [Abstract]
Net income	1,430			1,430
Other comprehensive income (loss), net of tax	628					628
Total comprehensive income	2,058
Dividends to shareholders	(390)			(390)
Repurchase of common shares (in shares)		(10,597,948)
Repurchase of common shares	(1,442)				(1,442)
Share-based compensation plans (in shares)		1,672,297
Share-based compensation plans	188		132		56
Ending balance (in shares) at Sep. 30, 2019		127,405,096
Ending balance at Sep. 30, 2019	5,997	$ 3	8,392	13,944	(16,679)	337
Beginning balance (in shares) at Jun. 30, 2019		131,292,759
Beginning balance at Jun. 30, 2019	6,030	$ 3	8,337	13,530	(16,109)	269
Comprehensive income (loss) [Abstract]
Net income	543			543
Other comprehensive income (loss), net of tax	68					68
Total comprehensive income	611
Dividends to shareholders	(129)			(129)
Repurchase of common shares (in shares)		(4,145,672)
Repurchase of common shares	(570)				(570)
Share-based compensation plans (in shares)		258,009
Share-based compensation plans	55		55		0
Ending balance (in shares) at Sep. 30, 2019		127,405,096
Ending balance at Sep. 30, 2019	$ 5,997	$ 3	$ 8,392	$ 13,944	$ (16,679)	$ 337