Summary of Significant Accounting Policies (EPS) (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	3 Months Ended		9 Months Ended
	Oct. 31, 2021	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Basic (loss) earnings per share:
Net (loss) income attributable to common shareholders		$ (341)	$ (288)	$ 236	$ 213
Net (loss) income available to common shareholders		$ (341)	$ (288)	$ 236	$ 213
Weighted average common shares outstanding (in shares)		380,000,000	378,000,000	380,000,000	371,000,000
Basic (loss) earnings per share (in dollars per share)		$ (0.90)	$ (0.76)	$ 0.62	$ 0.57
Diluted (loss) earnings per share:
Net (loss) income attributable to common shareholders		$ (341)	$ (288)	$ 236	$ 213
Net (loss) income available to common shareholders		(341)	(288)	236	213
Net (loss) income available to common shareholders and assumed conversions		$ (341)	$ (288)	$ 236	$ 213
Weighted average common shares outstanding (in shares)		380,000,000	378,000,000	380,000,000	371,000,000
Incremental shares from assumed conversions (in shares)					1,000,000
Adjusted weighted average shares - diluted (in shares)		380,000,000	378,000,000	380,000,000	372,000,000
Diluted (loss) earnings per share (in dollars per share)		$ (0.90)	$ (0.76)	$ 0.62	$ 0.57
Antidilutive stock option awards excluded from earnings per share, number of shares		11,315,504	9,158,974	11,351,651	9,079,789
Storage
Diluted (loss) earnings per share:
Expected spending	$ 1,000
Potental contract termination cost	$ 500