Borrowings (Schedule Of Long-Term Borrowings) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Total Borrowings	$ 8,974.4	$ 14,935.5
CIT Group Inc.
Debt Instrument [Line Items]
Total Borrowings	3,737.5	10,599.0
Subsidiaries
Debt Instrument [Line Items]
Total Borrowings	5,236.9
Senior Unsecured
Debt Instrument [Line Items]
Total Borrowings	3,737.5	10,599.0
Senior Unsecured | CIT Group Inc.
Debt Instrument [Line Items]
Total Borrowings	3,737.5
Senior Unsecured | Subsidiaries
Debt Instrument [Line Items]
Total Borrowings	0.0
Structured financings
Debt Instrument [Line Items]
Total Borrowings	1,541.4	1,925.7
Structured financings | CIT Group Inc.
Debt Instrument [Line Items]
Total Borrowings	0.0
Structured financings | Subsidiaries
Debt Instrument [Line Items]
Total Borrowings	1,541.4
FHLB advances
Debt Instrument [Line Items]
Total Borrowings	3,695.5	$ 2,410.8
FHLB advances | CIT Group Inc.
Debt Instrument [Line Items]
Total Borrowings	0.0
FHLB advances | Subsidiaries
Debt Instrument [Line Items]
Total Borrowings	$ 3,695.5