Guarantor Condensed Consolidating Financial Statements (Condensed Consolidating Balance Sheets) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Current assets:
Cash and cash equivalents	$ 727.4	$ 740.5	$ 762.0	$ 585.2
Cash and cash equivalents of consolidated investment products	382.3	636.7
Unsettled fund receivables	444.4	513.4
Accounts receivable	424.4	424.7
Accounts receivable of consolidated investment products	98.5	158.8
Investments	283.7	308.8
Prepaid assets	51.2	64.0
Other current assets	150.0	101.8
Deferred tax asset, net	28.7	30.4
Assets held for policyholders	1,243.5	1,295.4
Total current assets	3,834.1	4,274.5
Non-current assets:
Investments	200.8	164.4
Investments of consolidated investment products	6,629.0	7,206.0
Security deposit assets and receivables	81.2	146.3
Other non-current assets	17.9	20.9
Deferred sales commissions	40.5	42.2
Property and equipment, net	312.8	272.4
Intangible assets, net	1,322.8	1,337.2
Goodwill	6,907.9	6,980.2	6,467.6
Total non-current assets	15,512.9	16,169.6
Total assets	19,347.0	20,444.1
Current liabilities:
Current maturities of total debt	215.1	0
Unsettled fund payables	439.6	504.8
Income taxes payable	59.6	72.2
Other current liabilities	841.5	905.7
Other current liabilities of consolidated investment products	175.1	486.4
Policyholder payables	1,243.5	1,295.4
Total current liabilities	2,974.4	3,264.5
Non-current liabilities:
Long-term debt	1,069.6	1,315.7
Long-term debt of consolidated investment products	5,512.9	5,865.4
Security deposits payable	81.2	146.3
Other non-current liabilities	297.3	262.3
Total non-current liabilities	7,235.0	7,818.7
Total liabilities	10,209.4	11,083.2
Total equity attributable to common shareholders	8,119.1	8,264.6
Equity attributable to noncontrolling interests in consolidated entities	1,018.5	1,096.3
Total equity	9,137.6	9,360.9	7,620.8	6,596.2
Total liabilities and equity	19,347.0	20,444.1
Guarantors [Member]
Current assets:
Cash and cash equivalents	20.6	12.4	100.4	422.4
Cash and cash equivalents of consolidated investment products	0	0
Unsettled fund receivables	0	0
Accounts receivable	163.6	100.5
Accounts receivable of consolidated investment products	0	0
Investments	4.2	7.4
Prepaid assets	9.7	9.6
Other current assets	39.3	39.6
Deferred tax asset, net	18.9	14.6
Assets held for policyholders	0	0
Intercompany receivables	477.0	320.3
Total current assets	733.3	504.4
Non-current assets:
Investments	50.0	35.3
Investments of consolidated investment products	0	0
Security deposit assets and receivables	0	0
Other non-current assets	8.5	2.8
Deferred sales commissions	13.9	12.2
Property and equipment, net	145.3	122.9
Intangible assets, net	420.6	393.9
Goodwill	2,312.8	2,322.9
Intercompany receivables	333.0	0
Investments in subsidiaries	1,228.2	1,333.8
Total non-current assets	4,512.3	4,223.8
Total assets	5,245.6	4,728.2
Current liabilities:
Current maturities of total debt	0
Unsettled fund payables	0	0
Income taxes payable	0	0
Other current liabilities	144.3	120.9
Other current liabilities of consolidated investment products	0	0
Policyholder payables	0	0
Intercompany payables	366.5	302.3
Total current liabilities	510.8	423.2
Non-current liabilities:
Long-term debt	539.0	570.0
Long-term debt of consolidated investment products	0	0
Deferred tax liabilities, net	29.6	10.1
Security deposits payable	0	0
Other non-current liabilities	55.1	27.0
Intercompany payables	1,361.8	1,317.8
Total non-current liabilities	1,985.5	1,924.9
Total liabilities	2,496.3	2,348.1
Total equity attributable to common shareholders	2,749.3	2,380.1
Equity attributable to noncontrolling interests in consolidated entities	0	0
Total equity	2,749.3	2,380.1
Total liabilities and equity	5,245.6	4,728.2
Non-Guarantors [Member]
Current assets:
Cash and cash equivalents	703.2	725.9	660.6	161.0
Cash and cash equivalents of consolidated investment products	382.3	636.7
Unsettled fund receivables	444.4	513.4
Accounts receivable	260.8	324.2
Accounts receivable of consolidated investment products	98.5	158.8
Investments	266.2	269.5
Prepaid assets	41.5	54.4
Other current assets	120.3	67.9
Deferred tax asset, net	9.8	15.8
Assets held for policyholders	1,243.5	1,295.4
Intercompany receivables	421.4	363.1
Total current assets	3,991.9	4,425.1
Non-current assets:
Investments	144.4	125.0
Investments of consolidated investment products	6,629.0	7,206.0
Security deposit assets and receivables	81.2	146.3
Other non-current assets	6.6	14.8
Deferred sales commissions	26.6	30.0
Property and equipment, net	167.5	149.5
Intangible assets, net	902.2	943.3
Goodwill	4,161.8	4,216.5
Intercompany receivables	1,450.5	1,403.1
Investments in subsidiaries	5.6	5.5
Total non-current assets	13,575.4	14,240.0
Total assets	17,567.3	18,665.1
Current liabilities:
Current maturities of total debt	0
Unsettled fund payables	439.6	504.8
Income taxes payable	63.1	84.7
Other current liabilities	685.4	774.5
Other current liabilities of consolidated investment products	175.1	486.4
Policyholder payables	1,243.5	1,295.4
Intercompany payables	507.5	316.5
Total current liabilities	3,114.2	3,462.3
Non-current liabilities:
Long-term debt	0	0
Long-term debt of consolidated investment products	5,512.9	5,865.4
Deferred tax liabilities, net	244.4	218.9
Security deposits payable	81.2	146.3
Other non-current liabilities	242.2	235.3
Intercompany payables	0	0
Total non-current liabilities	6,080.7	6,465.9
Total liabilities	9,194.9	9,928.2
Total equity attributable to common shareholders	7,353.9	7,640.6
Equity attributable to noncontrolling interests in consolidated entities	1,018.5	1,096.3
Total equity	8,372.4	8,736.9
Total liabilities and equity	17,567.3	18,665.1
Issuer [Member]
Current assets:
Cash and cash equivalents	3.1	1.1	0.2	1.7
Cash and cash equivalents of consolidated investment products	0	0
Unsettled fund receivables	0	0
Accounts receivable	0	0
Accounts receivable of consolidated investment products	0	0
Investments	0	0
Prepaid assets	0	0
Other current assets	1.1	6.1
Deferred tax asset, net	0	0
Assets held for policyholders	0	0
Intercompany receivables	34.8	153.0
Total current assets	39.0	160.2
Non-current assets:
Investments	3.4	1.7
Investments of consolidated investment products	0	0
Security deposit assets and receivables	0	0
Other non-current assets	2.8	2.8
Deferred sales commissions	0	0
Property and equipment, net	0	0
Intangible assets, net	0	0
Goodwill	433.3	440.8
Intercompany receivables	567.8	567.8
Investments in subsidiaries	5,116.3	4,766.1
Total non-current assets	6,123.6	5,779.2
Total assets	6,162.6	5,939.4
Current liabilities:
Current maturities of total debt	215.1
Unsettled fund payables	0	0
Income taxes payable	7.4	0
Other current liabilities	11.1	9.6
Other current liabilities of consolidated investment products	0	0
Policyholder payables	0	0
Intercompany payables	29.9	45.7
Total current liabilities	263.5	55.3
Non-current liabilities:
Long-term debt	530.6	745.7
Long-term debt of consolidated investment products	0	0
Deferred tax liabilities, net	0	0
Security deposits payable	0	0
Other non-current liabilities	0	0
Intercompany payables	656.6	653.1
Total non-current liabilities	1,187.2	1,398.8
Total liabilities	1,450.7	1,454.1
Total equity attributable to common shareholders	4,711.9	4,485.3
Equity attributable to noncontrolling interests in consolidated entities	0	0
Total equity	4,711.9	4,485.3
Total liabilities and equity	6,162.6	5,939.4
Parent Company [Member]
Current assets:
Cash and cash equivalents	0.5	1.1	0.8	0.1
Cash and cash equivalents of consolidated investment products	0	0
Unsettled fund receivables	0	0
Accounts receivable	0	0
Accounts receivable of consolidated investment products	0	0
Investments	13.3	31.9
Prepaid assets	0	0
Other current assets	0.2	0.7
Deferred tax asset, net	0	0
Assets held for policyholders	0	0
Intercompany receivables	0	0
Total current assets	14.0	33.7
Non-current assets:
Investments	3.0	2.4
Investments of consolidated investment products	0	0
Security deposit assets and receivables	0	0
Other non-current assets	0	0.5
Deferred sales commissions	0	0
Property and equipment, net	0	0
Intangible assets, net	0	0
Goodwill	0	0
Intercompany receivables	0	0
Investments in subsidiaries	8,465.0	8,400.6
Total non-current assets	8,468.0	8,403.5
Total assets	8,482.0	8,437.2
Current liabilities:
Current maturities of total debt	0
Unsettled fund payables	0	0
Income taxes payable	0	0
Other current liabilities	0.7	0.7
Other current liabilities of consolidated investment products	0	0
Policyholder payables	0	0
Intercompany payables	29.3	171.9
Total current liabilities	30.0	172.6
Non-current liabilities:
Long-term debt	0	0
Long-term debt of consolidated investment products	0	0
Deferred tax liabilities, net	0	0
Security deposits payable	0	0
Other non-current liabilities	0	0
Intercompany payables	332.9	0
Total non-current liabilities	332.9	0
Total liabilities	362.9	172.6
Total equity attributable to common shareholders	8,119.1	8,264.6
Equity attributable to noncontrolling interests in consolidated entities	0	0
Total equity	8,119.1	8,264.6
Total liabilities and equity	8,482.0	8,437.2
Adjustments [Member]
Current assets:
Cash and cash equivalents	0	0	0	0
Cash and cash equivalents of consolidated investment products	0	0
Unsettled fund receivables	0	0
Accounts receivable	0	0
Accounts receivable of consolidated investment products	0	0
Investments	0	0
Prepaid assets	0	0
Other current assets	(10.9)	(12.5)
Deferred tax asset, net	0	0
Assets held for policyholders	0	0
Intercompany receivables	(933.2)	(836.4)
Total current assets	(944.1)	(848.9)
Non-current assets:
Investments	0	0
Investments of consolidated investment products	0	0
Security deposit assets and receivables	0	0
Other non-current assets	0	0
Deferred sales commissions	0	0
Property and equipment, net	0	0
Intangible assets, net	0	0
Goodwill	0	0
Intercompany receivables	(2,351.3)	(1,970.9)
Investments in subsidiaries	(14,815.1)	(14,506.0)
Total non-current assets	(17,166.4)	(16,476.9)
Total assets	(18,110.5)	(17,325.8)
Current liabilities:
Current maturities of total debt	0
Unsettled fund payables	0	0
Income taxes payable	(10.9)	(12.5)
Other current liabilities	0	0
Other current liabilities of consolidated investment products	0	0
Policyholder payables	0	0
Intercompany payables	(933.2)	(836.4)
Total current liabilities	(944.1)	(848.9)
Non-current liabilities:
Long-term debt	0	0
Long-term debt of consolidated investment products	0	0
Deferred tax liabilities, net	0	0
Security deposits payable	0	0
Other non-current liabilities	0	0
Intercompany payables	(2,351.3)	(1,970.9)
Total non-current liabilities	(2,351.3)	(1,970.9)
Total liabilities	(3,295.4)	(2,819.8)
Total equity attributable to common shareholders	(14,815.1)	(14,506.0)
Equity attributable to noncontrolling interests in consolidated entities	0	0
Total equity	(14,815.1)	(14,506.0)
Total liabilities and equity	(18,110.5)	(17,325.8)
Consolidated [Member]
Current assets:
Cash and cash equivalents	727.4	740.5	762.0	585.2
Cash and cash equivalents of consolidated investment products	382.3	636.7
Unsettled fund receivables	444.4	513.4
Accounts receivable	424.4	424.7
Accounts receivable of consolidated investment products	98.5	158.8
Investments	283.7	308.8
Prepaid assets	51.2	64.0
Other current assets	150.0	101.8
Deferred tax asset, net	28.7	30.4
Assets held for policyholders	1,243.5	1,295.4
Intercompany receivables	0	0
Total current assets	3,834.1	4,274.5
Non-current assets:
Investments	200.8	164.4
Investments of consolidated investment products	6,629.0	7,206.0
Security deposit assets and receivables	81.2	146.3
Other non-current assets	17.9	20.9
Deferred sales commissions	40.5	42.2
Property and equipment, net	312.8	272.4
Intangible assets, net	1,322.8	1,337.2
Goodwill	6,907.9	6,980.2
Intercompany receivables	0	0
Investments in subsidiaries	0	0
Total non-current assets	15,512.9	16,169.6
Total assets	19,347.0	20,444.1
Current liabilities:
Current maturities of total debt	215.1
Unsettled fund payables	439.6	504.8
Income taxes payable	59.6	72.2
Other current liabilities	841.5	905.7
Other current liabilities of consolidated investment products	175.1	486.4
Policyholder payables	1,243.5	1,295.4
Intercompany payables	0	0
Total current liabilities	2,974.4	3,264.5
Non-current liabilities:
Long-term debt	1,069.6	1,315.7
Long-term debt of consolidated investment products	5,512.9	5,865.4
Deferred tax liabilities, net	274.0	229.0
Security deposits payable	81.2	146.3
Other non-current liabilities	297.3	262.3
Intercompany payables	0	0
Total non-current liabilities	7,235.0	7,818.7
Total liabilities	10,209.4	11,083.2
Total equity attributable to common shareholders	8,119.1	8,264.6
Equity attributable to noncontrolling interests in consolidated entities	1,018.5	1,096.3
Total equity	9,137.6	9,360.9
Total liabilities and equity	$ 19,347.0	$ 20,444.1