Equity Preferred Stock (Details) - USD ($) $ / shares in Units, $ in Millions		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2020	Dec. 31, 2019
Preference Share, Series A
Class of Stock [Line Items]
Preferred Stock, Shares Issued	34,500	34,500	0
Preferred Stock, Shares Authorized	34,500	34,500	34,500
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		$ 793.76
Dividends, Preferred Stock, Cash		$ 27
Preferred Stock, Shares Outstanding	34,500	34,500	0
Preference Share, Series B
Class of Stock [Line Items]
Preferred Stock, Shares Issued	13,800	13,800	0
Preferred Stock, Shares Authorized	13,800	13,800	13,800
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		$ 703.12
Dividends, Preferred Stock, Cash		$ 10
Preferred Stock, Shares Outstanding	13,800	13,800	0
Preference Share, Series C
Class of Stock [Line Items]
Preferred Stock, Shares Issued	24,000	24,000	0
Preferred Stock, Shares Authorized	24,000	24,000	0
Preferred Stock, Dividend Rate, Percentage	6.375%
Preferred Stock, Par or Stated Value Per Share	$ 1	$ 1	$ 0
Preferred Stock, Liquidation Preference Per Share	$ 25,000	25,000
Preferred Stock, Dividends, Per Share, Cash Paid		$ 0
Dividends, Preferred Stock, Cash		$ 0
Preferred Stock, Shares Outstanding	24,000	24,000	0