Investment Securities (Fair Value of Hedge Funds Subject to Restrictions on Redemption Frequency) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Private equity funds
Investment securities
Trading Securities, Other	$ 118.2
Hedge funds
Investment securities
Trading Securities, Other	120.8
Total hedge and private equity funds included in other long-term investments
Investment securities
Trading Securities, Other	239.0	239.8
Fair value unfunded commitments	110.6	119.4
Other Long-term Investments Largest Single Investment	18.3	16.0
Private equity funds | Private equity funds
Investment securities
Trading Securities, Other	118.2	125.2
Fair value unfunded commitments	110.6	119.4
Private equity funds | Multi-sector
Investment securities
Trading Securities, Other	23.8	23.3
Fair value unfunded commitments	6.5	5.4
Private equity funds | Energy infrastructure & services
Investment securities
Trading Securities, Other	45.9	36.3
Fair value unfunded commitments	13.1	15.6
Private equity funds | Distressed residential real estate
Investment securities
Trading Securities, Other	0.4	15.8
Fair value unfunded commitments	0	0
Private equity funds | Real estate
Investment securities
Trading Securities, Other	8.2	11.6
Fair value unfunded commitments	3.3	3.3
Private equity funds | Private equity secondaries
Investment securities
Trading Securities, Other	9.5	10.5
Fair value unfunded commitments	3.1	3.1
Private equity funds | International multi-sector, Europe
Investment securities
Trading Securities, Other	3.9	5.1
Fair value unfunded commitments	2.8	5.0
Private equity funds | Manufacturing/Industrial
Investment securities
Trading Securities, Other	11.2	9.9
Fair value unfunded commitments	15.5	15.1
Private equity funds | Healthcare
Investment securities
Trading Securities, Other	5.6	4.3
Fair value unfunded commitments	2.8	5.4
Private equity funds | International multi-sector, Asia
Investment securities
Trading Securities, Other	0	0.4
Fair value unfunded commitments	2.7	2.7
Private equity funds | Insurance
Investment securities
Trading Securities, Other	2.3	3.0
Fair value unfunded commitments	41.3	41.3
Private equity funds | Aerospace/Defense/Government
Investment securities
Trading Securities, Other	5.8	2.8
Fair value unfunded commitments	19.2	22.2
Private equity funds | Venture capital
Investment securities
Trading Securities, Other	1.6	2.2
Fair value unfunded commitments	0.3	0.3
Hedge funds | Hedge funds
Investment securities
Trading Securities, Other	120.8	114.6
Fair value unfunded commitments	0	0
Hedge funds | Long/short equity
Investment securities
Trading Securities, Other	62.6	60.3
Fair value unfunded commitments	0	0
Hedge funds | Long/short credit & distressed
Investment securities
Trading Securities, Other	22.8	22.7
Fair value unfunded commitments	0	0
Hedge funds | Long diversified strategies
Investment securities
Trading Securities, Other	0.1	1.7
Fair value unfunded commitments	0	0
Hedge funds | Long/short equity REIT
Investment securities
Trading Securities, Other	18.3	16.0
Fair value unfunded commitments	0	0
Hedge funds | Long/short equity activist
Investment securities
Trading Securities, Other	16.8	13.6
Fair value unfunded commitments	0	0
Hedge funds | Long bank loan
Investment securities
Trading Securities, Other	0.2	0.3
Fair value unfunded commitments	$ 0	$ 0