Acquisitions, Discontinued Operations and Dispositions - Direct Energy Measurement Period Adjustment (Details) - Direct Energy $ in Millions	3 Months Ended
	Dec. 31, 2021 USD ($)
Assets
Prepayments and other current assets	$ (10)
Goodwill	(7)
Total decrease in assets	(17)
Liabilities
Accounts payable	(4)
Accrued expenses and other current liabilities	(20)
Deferred income taxes	(18)
Total decrease in liabilities	(42)
Net measurement period adjustments	$ 25