Contingencies (Details) (USD $) In Millions, unless otherwise specified	1 Months Ended	3 Months Ended		12 Months Ended
	Apr. 30, 2011	Mar. 31, 2012	Jun. 30, 2011	Dec. 31, 2009	Dec. 31, 2011
Loss Contingencies [Line Items]
Liabilities for 2000 Distribution Agreement and Liabilities for Legacy Tax Matters, Liability for the remaining potential exposure		$ 53.5			$ 52.6
Anticipated future tax benefits		50.00%
Reduction of interest expense			2.8	6.5
Reduction in interest expense, net of tax			1.7
Increase in other non-operating income			6.4
Legacy refund	0.9
Legacy refund, net	0.6
Reduction of tax expense				4.3
Deposit with IRS to stop the accrual of statutory interest on potential tax deficiencies with respect to the 1997 through 2002 tax years, New D&B and Moody's commenced procedures to recover approximately		11.9			12.2
Legacy Tax Matters 1989-1990 And 1993-1996 [Member]
Loss Contingencies [Line Items]
Liabilities for 2000 Distribution Agreement and Liabilities for Legacy Tax Matters, Liability for the remaining potential exposure		55.5
Liability for legacy tax matters		2
Legacy Tax Matters [Member]
Loss Contingencies [Line Items]
Proceeds from IMS Health, NMR arbitration settlements and New D&B for 50% of the anticipated future tax benefits through 2012		55.0
Legacy Tax Matters IMS Health And NMR 1993 - 1996 [Member]
Loss Contingencies [Line Items]
Proceeds from IMS Health, NMR arbitration settlements and New D&B for 50% of the anticipated future tax benefits through 2012				10.8
Benefit to net income related to the resolution of legacy tax matters				8.2
Legacy Tax Matters Amortization Expense Deductions 2000 Distribution Agreement [Member]
Loss Contingencies [Line Items]
Liabilities for 2000 Distribution Agreement and Liabilities for Legacy Tax Matters, Liability for the remaining potential exposure		$ 53.5