Shareholders' Equity - Narrative (Details) - USD ($)																12 Months Ended
	Dec. 27, 2019	Dec. 19, 2019	Aug. 06, 2019	Jun. 19, 2019	Jun. 11, 2019	Jun. 04, 2019	Apr. 09, 2019	Apr. 04, 2019	Jan. 03, 2019	Sep. 12, 2018	Mar. 26, 2018	Dec. 26, 2017	Apr. 12, 2017	Mar. 09, 2017	May 07, 2013	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Oct. 31, 2019	May 02, 2019
Class of stock [Line Items]
Amount authorized for repurchase																			$ 800	$ 500
Dividend per share, cash paid (usd per share)	$ 0.15														$ 0.01
Fair value of warrants issued															$ 94,000,000
Warrants exercised																0
Exercise price of warrants (usd per share)	$ 48.49														$ 48.75
Number of shares of common stock for which each warrant is exercisable (in shares)	1.002430429
Percentage of issued warrants to total shares issued and outstanding															9.99%
Number of warrants issued and outstanding															26,050,846
Preferred stock, par value																$ 0.01	$ 0.01
Proceeds from issuance of preferred stock, net																$ 293,000,000	$ 319,000,000	$ 0
Issuer's redemption option, period to redeem after a redemption event																90 days
Preferred stock, shares authorized (in shares)																100,000,000	100,000,000
Preferred stock dividends in arrears																$ 0
Common stock acquired - Share repurchase		$ (200,000,000)		$ (200,000,000)			$ (236,000,000)		$ (250,000,000)			$ (500,000,000)		$ (150,000,000)		$ (1,136,000,000)	$ (1,025,000,000)	$ (923,000,000)
Number of shares repurchased and placed in treasury		2,591,093	695,566	2,963,512		879,199	3,593,453	290,765	5,059,449		1,947,413	7,821,666	3,986,647	0		21,100,000	(22,800,000)	24,400,000
Rating Agency Event
Class of stock [Line Items]
Redemption price (in dollars per share)																$ 1,020
Regulatory Capital Event
Class of stock [Line Items]
Redemption price (in dollars per share)																$ 1,000
Open market repurchase
Class of stock [Line Items]
Common stock acquired - Share repurchase																$ (250,000,000)	$ (1,025,000,000)	$ (273,000,000)
Number of shares repurchased and placed in treasury																4,926,775	20,843,047	7,437,994
Series B Preferred Stock
Class of stock [Line Items]
Preferred stock, shares issued (in shares)					300,000											300,000	0
Preferred stock, dividend rate, percentage					5.35%											5.35%
Preferred stock, par value					$ 0.01
Liquidation preference (in dollars per share)					$ 1,000
Proceeds from issuance of preferred stock, net					$ 293
Series A Preferred Stock
Class of stock [Line Items]
Preferred stock, shares issued (in shares)										325,000						325,000	325,000
Preferred stock, dividend rate, percentage										6.125%						5.125%
Preferred stock, par value										$ 0.01
Liquidation preference (in dollars per share)										$ 1,000
Proceeds from issuance of preferred stock, net										$ 319,000,000
Depositary Shares | Rating Agency Event
Class of stock [Line Items]
Redemption price (in dollars per share)																$ 25.50
Depositary Shares | Regulatory Capital Event
Class of stock [Line Items]
Redemption price (in dollars per share)																$ 25.00