Fair Value Of Assets And Liabilities (Tri-Level Hierarchy, Carrying Value) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012		Dec. 31, 2011
Money market funds	$ 234.7		$ 257.7
Seed money	113.2	[1]	63.5	[1]
Investments related to deferred compensation plans	211.7	[1]	184.4	[2]
Corporate Stock	1.4	[1]	1.1	[2]
UITs	1.3	[1]	0.9	[2]
Municipal securities	2.7	[1]	1.1	[2]
Assets held for policyholders	1,139.3		1,243.5
Option contracts	0.1
Current Assets, Fair Value Disclosure	1,704.4		1,752.2
CLOs	2.5	[1]
other debt securities	6.3	[1]
Total assets at fair value	1,713.2
Policyholder payables	(1,139.3)		(1,243.5)
Corporate equities	(1.3)		(1.0)
Note payable	(11.3)		(16.8)
Total liabilities at fair value	(1,151.9)		(1,261.3)
Foreign time deposits	33.4		32.2
Other current investments	0.5		0.5
Equity method investments	202.9		193.1
Other non-current cost method investments	11.8		7.7
Quoted Prices in Active Markets for Identical Assets [Member]
Money market funds	234.7		257.7
Seed money	113.2	[1]	63.5	[1]
Investments related to deferred compensation plans	211.7	[1]	184.4	[2]
Corporate Stock	1.4	[1]	1.1	[2]
UITs	1.3	[1]	0.9	[2]
Municipal securities	0	[1]	0	[2]
Assets held for policyholders	1,139.3		1,243.5
Option contracts	0
Current Assets, Fair Value Disclosure	1,701.6		1,751.1
CLOs	0	[1]
other debt securities	0	[1]
Total assets at fair value	1,701.6
Policyholder payables	(1,139.3)		(1,243.5)
Corporate equities	(1.3)		(1.0)
Note payable	0		0
Total liabilities at fair value	(1,140.6)		(1,244.5)
Significant Other Observable Inputs [Member]
Money market funds	0		0
Seed money	0	[1]	0	[1]
Investments related to deferred compensation plans	0	[1]	0	[2]
Corporate Stock	0	[1]	0	[2]
UITs	0	[1]	0	[2]
Municipal securities	2.7	[1]	1.1	[2]
Assets held for policyholders	0		0
Option contracts	0.1
Current Assets, Fair Value Disclosure	2.8		1.1
CLOs	0	[1]
other debt securities	0	[1]
Total assets at fair value	2.8
Policyholder payables	0		0
Corporate equities	0		0
Note payable	0		0
Total liabilities at fair value	0		0
Significant Unobservable Inputs [Member]
Money market funds	0		0
Seed money	0	[1]	0	[1]
Investments related to deferred compensation plans	0	[1]	0	[2]
Corporate Stock	0	[1]	0	[2]
UITs	0	[1]	0	[2]
Municipal securities	0	[1]	0	[2]
Assets held for policyholders	0		0
Option contracts	0
Current Assets, Fair Value Disclosure	0		0
CLOs	2.5	[1]
other debt securities	6.3	[1]
Total assets at fair value	8.8
Policyholder payables	0		0
Corporate equities	0		0
Note payable	(11.3)		(16.8)
Total liabilities at fair value	$ (11.3)		$ (16.8)

[1] Current foreign time deposits of $33.4 million and other current investments of $0.5 million are excluded from this table. Non-current equity method and other investments of $202.9 million and $11.8 million, respectively, are also excluded from this table. These investments are not measured at fair value, in accordance with applicable accounting standards.

[2] Current foreign time deposits of $32.2 million and other current investments of $0.5 million are excluded from this table. Non-current equity method and other investments of $193.1 million and $7.7 million, respectively, are also excluded from this table. These investments are not measured at fair value, in accordance with applicable accounting standards.