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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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Gross number of shares (or other type of equity) issued during the period as a result of any equity-based compensation plan other than an employee stock ownership plan (ESOP). Shares issued could result from the issuance of restricted stock, the exercise of stock options, stock issued under employee stock purchase plans, and/or other employee benefit plans.

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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	1,056			1,056
Other comprehensive income (loss), net of tax	(407)					(407)
Total comprehensive income	649
Dividends to shareholders	(257)			(257)
Repurchase of common shares (in shares)		(5,978,029)
Repurchase of common shares	(900)				(900)
Share-based compensation plans (in shares)		1,563,776
Share-based compensation plans	145		86		59
Ending balance (in shares) at Jun. 30, 2018		142,220,411
Ending balance at Jun. 30, 2018	5,632	$ 3	8,171	12,126	(14,489)	(179)
Beginning balance (in shares) at Mar. 31, 2018		145,018,357
Beginning balance at Mar. 31, 2018	5,840	$ 3	8,116	11,796	(14,070)	(5)
Comprehensive income (loss) [Abstract]
Net income	462			462
Other comprehensive income (loss), net of tax	(174)					(174)
Total comprehensive income	288
Dividends to shareholders	(132)			(132)
Repurchase of common shares (in shares)		(2,974,300)
Repurchase of common shares	(418)				(418)
Share-based compensation plans (in shares)		176,354
Share-based compensation plans	54		55		(1)
Ending balance (in shares) at Jun. 30, 2018		142,220,411
Ending balance at Jun. 30, 2018	5,632	$ 3	8,171	12,126	(14,489)	(179)
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	887			887
Other comprehensive income (loss), net of tax	560					560
Total comprehensive income	1,447
Dividends to shareholders	(261)			(261)
Repurchase of common shares (in shares)		(6,452,276)
Repurchase of common shares	(872)				(872)
Share-based compensation plans (in shares)		1,414,288
Share-based compensation plans	133		77		56
Ending balance (in shares) at Jun. 30, 2019		131,292,759
Ending balance at Jun. 30, 2019	6,030	$ 3	8,337	13,530	(16,109)	269
Beginning balance (in shares) at Mar. 31, 2019		134,183,507
Beginning balance at Mar. 31, 2019	5,843	$ 3	8,270	13,172	(15,637)	35
Comprehensive income (loss) [Abstract]
Net income	492			492
Other comprehensive income (loss), net of tax	234					234
Total comprehensive income	726
Dividends to shareholders	(134)			(134)
Repurchase of common shares (in shares)		(3,252,369)
Repurchase of common shares	(473)				(473)
Share-based compensation plans (in shares)		361,621
Share-based compensation plans	68		67		1
Ending balance (in shares) at Jun. 30, 2019		131,292,759
Ending balance at Jun. 30, 2019	$ 6,030	$ 3	$ 8,337	$ 13,530	$ (16,109)	$ 269