Preferred Stock - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2000	Dec. 31, 2019
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares)	5,000,000		5,000,000
Preferred stock, shares outstanding (in shares)	26,250
Liquidation Amount	$ 488
Noncontrolling interest	$ 295		$ 295
Preferred stock, shares issued (in shares)	26,250		1,000
LIBOR | Beginning on or after August 1, 2025
Class of Stock [Line Items]
Basis spread on variable rate	4.262%
LIBOR | Beginning on or after May 1, 2026
Class of Stock [Line Items]
Basis spread on variable rate	4.92%
LIBOR | Beginning on or after May 1, 2024
Class of Stock [Line Items]
Basis spread on variable rate	3.859%
Series A
Class of Stock [Line Items]
Preferred stock, shares outstanding (in shares)	1,000
Liquidation Amount	$ 100
Annual Dividend Rate	6.20%
Series B
Class of Stock [Line Items]
Preferred stock, shares outstanding (in shares)	8,000
Liquidation Amount	$ 80
Annual Dividend Rate	6.625%
Series C
Class of Stock [Line Items]
Preferred stock, shares outstanding (in shares)	5,750
Liquidation Amount	$ 58
Annual Dividend Rate	6.60%
Series D
Class of Stock [Line Items]
Preferred stock, shares outstanding (in shares)	10,000
Liquidation Amount	$ 100
Annual Dividend Rate	6.10%
Series E
Class of Stock [Line Items]
Preferred stock, shares outstanding (in shares)	1,500
Liquidation Amount	$ 150
Annual Dividend Rate	6.50%
Preferred Class A
Class of Stock [Line Items]
Annual Dividend Rate	3.75%
Liquidation preference per share (in dollars per share)	$ 1,000
Noncontrolling interest	$ 295		$ 295
Preferred stock, shares issued (in shares)	300,000
Preferred Class A | LIBOR
Class of Stock [Line Items]
Basis spread on variable rate	0.85%
Preferred Class B | FT Real Estate Securities Company, Inc.
Class of Stock [Line Items]
Annual Dividend Rate		9.50%
Stock issued (in shares)		50
Liquidation preference per share (in dollars per share)		$ 1,000,000
Preferred Class B | Non Affiliates | FT Real Estate Securities Company, Inc.
Class of Stock [Line Items]
Stock issued (in shares)		47