Stockholders' Equity (Details) $ / shares in Units, $ in Millions			3 Months Ended	6 Months Ended
	Jul. 23, 2021 $ / shares	May 27, 2020 USD ($) $ / shares shares	Jun. 30, 2021 USD ($) $ / shares shares	Jun. 30, 2021 USD ($) day $ / shares shares	Jun. 30, 2020 USD ($)	Dec. 31, 2020 $ / shares shares
Class of Stock [Line Items]
Preferred Stock, Shares Authorized | shares			50,000,000	50,000,000		50,000,000
Preferred Stock, Shares Issued | shares			10,062,500	10,062,500		10,062,500
Net proceeds from issuance of preferred stock in connection with public offering | $				$ 0	$ 975
Payments of Dividends | $				$ 28	$ 0
Common Stock, Shares Authorized | shares			2,000,000,000	2,000,000,000		2,000,000,000
Common Stock, Par or Stated Value Per Share | $ / shares			$ 0.01	$ 0.01		$ 0.01
5.50% MCPS, Series A [Member]
Class of Stock [Line Items]
Preferred Stock, Shares Issued | shares		10,062,500
Net proceeds from issuance of preferred stock in connection with public offering | $		$ 975
Preferred Stock, Dividend Rate, Percentage				5.50%
Preferred Stock, Liquidation Preference Per Share | $ / shares		$ 100	$ 100	$ 100
Preferred Stock, Liquidation Preference, Value | $			$ 1,006	$ 1,006
Convertible Preferred Stock, Threshold Trading Days | day				20
Preferred Stock, Dividends, Per Share, Cash Paid | $ / shares			$ 1.375
5.50% MCPS, Series A [Member] | Minimum [Member]
Class of Stock [Line Items]
Convertible Preferred Stock, Shares Issued For Each Converted Share				2.3834
5.50% MCPS, Series A [Member] | Maximum [Member]
Class of Stock [Line Items]
Convertible Preferred Stock, Shares Issued For Each Converted Share				2.9197
5.50% MCPS, Series A [Member] | Subsequent Event [Member]
Class of Stock [Line Items]
Preferred Stock, Dividends Per Share, Declared | $ / shares	$ 1.375