Goodwill and Other Intangible Assets (Other Intangible Assets Associated with Acquisition) (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Net Carrying Amount	$ 662	$ 648
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Weighted-Average Remaining Amortization Period	5 years	6 years
Net Carrying Amount	$ 608	$ 638
Trade names and associated trademarks
Finite-Lived Intangible Assets [Line Items]
Weighted-Average Remaining Amortization Period	4 years	4 years
Net Carrying Amount	$ 9	$ 4
General Finance Corporation | Customer relationships
Finite-Lived Intangible Assets [Line Items]
Weighted-Average Remaining Amortization Period	7 years
Net Carrying Amount	$ 79
General Finance Corporation | Trade names and associated trademarks
Finite-Lived Intangible Assets [Line Items]
Weighted-Average Remaining Amortization Period	5 years
Net Carrying Amount	$ 6