Income Taxes (Narrative) (Details) (USD $)	3 Months Ended								12 Months Ended			60 Months Ended
	Apr. 30, 2013	Jan. 31, 2013	Oct. 31, 2012	Jul. 31, 2012	Apr. 30, 2012	Jan. 31, 2012	Oct. 31, 2011	Jul. 31, 2011	Apr. 30, 2013	Apr. 30, 2012	Apr. 30, 2011	Apr. 30, 2013	Apr. 30, 2010
Operating Loss Carryforwards [Line Items]
Net income (loss) from discontinued operations	$ (24,582,000)	$ (793,000)	$ (4,044,000)	$ (1,791,000)	$ (5,600,000)	$ 218,000	$ (18,711,000)	$ (55,943,000)	$ (31,210,000)	$ (80,036,000)	$ 13,563,000
Discontinued Operation, Tax Effect of Operations of Discontinued Operation									(19,662,000)	(13,329,000)	13,814,000
Tax expense (benefit) from discontinued operations										(74,900,000)
Effective tax rate on discontinued operations									38.60%	48.40%	50.50%
Deferred tax asset	229,332,000				235,385,000				229,332,000	235,385,000		229,332,000
Operating loss carryforwards	124,000,000								124,000,000			124,000,000
Unrecognized tax benefit	146,391,000				206,393,000				146,391,000	206,393,000	154,848,000	146,391,000	129,767,000
Unrecognized tax benefits that would impact effective tax rate	95,300,000				150,400,000				95,300,000	150,400,000	117,600,000	95,300,000
Effect of anticipated settlements of audit issues and expiring statutes of limitations	38,000,000								38,000,000			38,000,000
Increase (decrease) in gross interest and penalties accrued on uncertain tax positions										(5,500,000)	4,400,000	(6,900,000)
Total gross interest and penalties accrued	31,700,000				38,600,000				31,700,000	38,600,000	44,100,000	31,700,000
Valuation Allowance, Deferred Tax Asset, Change in Amount									22,800,000
Income Tax Reconciliation, Change in Deferred Tax Assets Valuation Allowance									(5,500,000)
Statutory federal tax rate									35.00%	35.00%	35.00%
Settlement reducing uncertain tax benefits									25,259,000	8,742,000	7,639,000
Income Taxes Receivable	151,300,000								151,300,000			151,300,000
Taxes Payable	15,200,000								15,200,000			15,200,000
Income Taxes, Net, Expected Federal Refund	136,100,000								136,100,000			136,100,000
Ameriprise
Operating Loss Carryforwards [Line Items]
Deferred tax asset	48,200,000				85,800,000				48,200,000	85,800,000		48,200,000
Valuation allowance	39,000,000				63,600,000				39,000,000	63,600,000		39,000,000
State And Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Deferred tax asset	20,100,000								20,100,000			20,100,000
Valuation allowance	14,400,000								14,400,000			14,400,000
1999 - 2007 Tax Returns [Member]
Operating Loss Carryforwards [Line Items]
Settlement reducing uncertain tax benefits									59,000,000
Income tax benefit									$ 33,300,000