General - Schedule of Net Income Available to Shareholders (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Net (Loss) Income Available to Common Stockholders	$ (306)	$ 556
Less: Net Income allocated to restricted stock awards(a)	$ (3)	$ (3)
Basic Weighted Average Common Shares Outstanding	2,264	2,262
Basic (Loss) Earnings Per Common Share	$ (0.14)	$ 0.24
Class P Common Stock
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Net (Loss) Income Available to Common Stockholders	$ (309)	$ 553
Unvested restricted stock awards | Class P Common Stock
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Restricted stock awards outstanding	12