Fair Value Of Assets And Liabilities (Tri-Level Hierarchy, Carrying Value) (Details) (USD $) In Millions	9 Months Ended		12 Months Ended
	Sep. 30, 2011		Dec. 31, 2010
Money market funds	$ 243.0		$ 316.4
Seed money	71.9	[1]	99.5	[2]
Investments related to deferred compensation plans	175.7	[1]	165.5	[2]
Corporate Stock	0.9	[1]	1.2	[2]
UITs	2.0		4.0	[2]
Municipal securities	5.2	[1]	9.9	[2]
Assets held for policyholders	1,255.3		1,295.4
Total current assets	1,754.0		1,891.9
CLOs	0.5	[1]	0.5	[2]
Total assets at fair value	1,754.5		1,892.4
Policyholder payables	(1,255.3)		(1,295.4)
Corporate equities	(1.1)		(0.7)
U.S. Treasury securities	(1.9)
UIT-related derivative liabilities			(0.1)
Notes payable, Non-current	(16.0)		(18.9)
Total liabilities at fair value	(1,274.3)		(1,315.1)
Foreign time deposits	39.0		28.2
Other current investments	0.5		0.5
Equity method investments	178.6		156.9
Other non-current cost method investments	7.8		7.0
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Money market funds	243.0		316.4
Seed money	71.9	[1]	99.5	[2]
Investments related to deferred compensation plans	175.7	[1]	165.5	[2]
Corporate Stock	0.9	[1]	1.2	[2]
UITs	2.0		4.0	[2]
Municipal securities	0	[1]	0	[2]
Assets held for policyholders	1,255.3		1,295.4
Total current assets	1,748.8		1,882.0
CLOs	0	[1]	0	[2]
Total assets at fair value	1,748.8		1,882.0
Policyholder payables	(1,255.3)		(1,295.4)
Corporate equities	(1.1)		(0.7)
U.S. Treasury securities	(1.9)
UIT-related derivative liabilities			(0.1)
Notes payable, Non-current	0		0
Total liabilities at fair value	(1,258.3)		(1,296.2)
Significant Other Observable Inputs (Level 2) [Member]
Money market funds	0		0
Seed money	0	[1]	0	[2]
Investments related to deferred compensation plans	0	[1]	0	[2]
Corporate Stock	0	[1]	0	[2]
UITs	0		0	[2]
Municipal securities	5.2	[1]	9.9	[2]
Assets held for policyholders	0		0
Total current assets	5.2		9.9
CLOs	0	[1]	0	[2]
Total assets at fair value	5.2		9.9
Policyholder payables	0		0
Corporate equities	0		0
U.S. Treasury securities	0
UIT-related derivative liabilities			0
Notes payable, Non-current	0		0
Total liabilities at fair value	0		0
Significant Unobservable Inputs (Level 3) [Member]
Money market funds	0		0
Seed money	0	[1]	0	[2]
Investments related to deferred compensation plans	0	[1]	0	[2]
Corporate Stock	0	[1]	0	[2]
UITs	0		0	[2]
Municipal securities	0	[1]	0	[2]
Assets held for policyholders	0		0
Total current assets	0		0
CLOs	0.5	[1]	0.5	[2]
Total assets at fair value	0.5		0.5
Policyholder payables	0		0
Corporate equities	0		0
U.S. Treasury securities	0
UIT-related derivative liabilities			0
Notes payable, Non-current	(16.0)		(18.9)
Total liabilities at fair value	$ (16.0)		$ (18.9)

[1] Current foreign time deposits of $39.0 million and other current investments of $0.5 million are excluded from this table. Other non-current equity and other investments of $178.6 million and $7.8 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 $28.2 million and other current investments of $0.5 million are excluded from this table. Other non-current equity and other investments of $156.9 million and $7.0 million, respectively, are also excluded from this table. These investments are not measured at fair value, in accordance with applicable accounting standards.