Shareholders' Equity (Details) $ / shares in Units, $ in Millions		1 Months Ended
	Sep. 01, 2017 $ / shares	Sep. 30, 2017 USD ($) $ / shares shares	Dec. 31, 2017 $ / shares	Aug. 31, 2017 $ / shares	Dec. 31, 2016 $ / shares
Class of Stock [Line Items]
Common stock par value per share (in usd per share)	$ 0.0001		$ 0.0001	$ 1	$ 0.0001
Preferred stock par value (in dollars per share)			$ 0.01		$ 0.01
Common Stock [Member]
Class of Stock [Line Items]
Stock split conversion ratio	10,000
Series A Preferred Stock [Member]
Class of Stock [Line Items]
Stock issued during period (shares) | shares		1,000,000
Preferred stock par value (in dollars per share)		$ 0.01
Preferred stock issued during period | $		$ 985
Liquidation preference (in dollars per share)		$ 1,000
Term of fixed rate dividend payments		10 years
Preferred stock dividend rate		5.75%
Series A Preferred Stock [Member] | London Interbank Offered Rate (LIBOR) [Member]
Class of Stock [Line Items]
Preferred stock variable dividend rate		3.598%