Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		15 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2020
Income Tax [Line Items]
Payroll tax deferral from CARES Act through December 2020			$ 73
Tax on subordinated interest gain (Vertiv)	$ 95
Favorable net discrete items, percentage impact	2.00%	2.00%
Payroll Taxes Paid	$ 37
Unfavorable discrete items, percentage impact	4.00%
Income taxes	$ 280	$ 111
Effective income tax rate	24.00%	20.00%