Subsequent Event (Details) - USD ($) $ / shares in Units, $ in Millions	Jul. 30, 2020	Jun. 30, 2020	Dec. 31, 2019
Subsequent Event [Line Items]
Preferred stock, liquidation preference per share (in dollars per share)		$ 25,000	$ 25,000
Subsequent Event
Subsequent Event [Line Items]
Number of shares issued in public offering	350,000
Proceeds from issuance of shares in public offering	$ 347
Subsequent Event | Preferred Stock, Series L
Subsequent Event [Line Items]
Preferred stock, issued (in shares)	14,000
Preferred stock, dividend rate	4.50%
Preferred stock, liquidation preference per share (in dollars per share)	$ 25,000
Preferred stock, redemption, percentage	100.00%
Subsequent Event | Preferred Stock, Series L | US Treasury Rate
Subsequent Event [Line Items]
Preferred stock, basis spread on variable rate	4.215%