Fair Value, Assets Measured on Recurring Basis (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
($ in millions)
Consumer	$ 665.9	$ 742.4
Energy	233.1	98.4
Financial services	702.5	527.7
Technical/communications	58.2	53.0
Transportation	110.1	39.1
Utilities	237.9	251.1
Other	199.6	185.8
Total corporates	2,207.3	1,897.5
Level 1
($ in millions)
Consumer	0	0
Energy	0	0
Financial services	0	0
Technical/communications	0	0
Transportation	0	0
Utilities	0	0
Other	0	0
Total corporates	0	0
Level 2
($ in millions)
Consumer	288.9	352.9
Energy	137.7	79.6
Financial services	440.3	361.9
Technical/communications	32.8	45.4
Transportation	25.0	9.3
Utilities	83.6	116.9
Other	96.7	130.0
Total corporates	1,105.0	1,096.0
Level 3
($ in millions)
Consumer	377.0	389.5
Energy	95.4	18.8
Financial services	262.2	165.8
Technical/communications	25.4	7.6
Transportation	85.1	29.8
Utilities	154.3	134.2
Other	102.9	55.8
Total corporates	$ 1,102.3	$ 801.5