Consolidated Balance Sheets Parenthetical - USD ($) shares in Millions, $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Accounts Receivable, Allowance for Credit Loss	$ 14.4	$ 12.6
Restricted cash, including partially-owned subsidiaries of $31.1 and $33.0	96.4	111.4
Property, plant, and equipment, at cost, including partially-owned subsidiaries of $1,931.6 and $2,065.3	9,193.0	9,272.5
Less accumulated depreciation, including partially-owned subsidiaries of $525.7 and $527.7	$ 2,189.6	$ 2,161.9
Preferred Stock, Shares Subscribed but Unissued	1.5	1.5
Preferred Stock, Shares Authorized	1.5	1.5
Common Stock, Shares Authorized	400.0	400.0
Common Stock [Member]
Common Stock, Shares, Issued	111.2	119.7
Treasury Stock [Member]
Common Stock, Shares, Issued	0.1	0.1
Operating Segments [Member] | Railcar Leasing and Management Services Group [Member]
Restricted cash, including partially-owned subsidiaries of $31.1 and $33.0	$ 96.3	$ 111.4
Partially-Owned Subsidiaries [Member]
Property, plant, and equipment, at cost, including partially-owned subsidiaries of $1,931.6 and $2,065.3	1,931.6	2,065.3
Less accumulated depreciation, including partially-owned subsidiaries of $525.7 and $527.7	525.7	527.7
Partially-Owned Subsidiaries [Member] | Operating Segments [Member] | Railcar Leasing and Management Services Group [Member]
Restricted cash, including partially-owned subsidiaries of $31.1 and $33.0	$ 31.1	$ 33.0