Equity Preferred Stock (Details) - USD ($)		3 Months Ended		9 Months Ended
	Jun. 30, 2020	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Class of Stock [Line Items]
Dividends, Preferred Stock, Cash		$ 30,000,000	$ 17,000,000	$ 67,000,000	$ 17,000,000
Preference Share, Series A
Class of Stock [Line Items]
Preferred Stock, Shares Issued		34,500		34,500		0.0
Preferred Stock, Shares Authorized		34,500		34,500		0.0
Preferred Stock, Dividend Rate, Percentage	6.35%
Preferred Stock, Par or Stated Value Per Share		$ 1		$ 1		$ 1
Preferred Stock, Liquidation Preference Per Share		25,000		25,000
Preferred Stock, Dividends, Per Share, Cash Paid		$ 396.87	$ 485.07	$ 1,190.63	$ 485.07
Dividends, Preferred Stock, Cash		$ 14,000,000	$ 17,000,000	$ 41,000,000	$ 17,000,000
Preferred Stock, Shares Outstanding		34,500		34,500		0.0
Preference Share, Series B
Class of Stock [Line Items]
Preferred Stock, Shares Issued		13,800		13,800		0.0
Preferred Stock, Shares Authorized		13,800		13,800		0.0
Preferred Stock, Dividend Rate, Percentage	5.625%
Preferred Stock, Par or Stated Value Per Share		$ 1		$ 1		$ 1
Preferred Stock, Liquidation Preference Per Share		25,000		25,000
Preferred Stock, Dividends, Per Share, Cash Paid		$ 351.57	$ 0	$ 1,054.69	$ 0
Dividends, Preferred Stock, Cash		$ 4,000,000	$ 0	$ 14,000,000	$ 0
Preferred Stock, Shares Outstanding		13,800		13,800		0.0
Preference Share, Series C
Class of Stock [Line Items]
Preferred Stock, Shares Issued		24,000		24,000
Preferred Stock, Shares Authorized		24,000		24,000
Preferred Stock, Dividend Rate, Percentage	6.375%
Preferred Stock, Par or Stated Value Per Share		$ 1		$ 1
Preferred Stock, Liquidation Preference Per Share		25,000		25,000
Preferred Stock, Dividends, Per Share, Cash Paid		$ 482.55	$ 0	$ 482.55	$ 0
Dividends, Preferred Stock, Cash		$ 12,000,000	$ 0	$ 12,000,000	$ 0
Preferred Stock, Shares Outstanding		24,000		24,000