Consolidated Balance Sheets (USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 814.7	$ 760.0
Short-term investments	13.3	14.8
Accounts receivable, net of allowances of $31.0 in 2012 and $28.0 in 2011	589.2	489.8
Deferred tax assets, net	41.4	82.2
Other current assets	68.0	77.6
Total current assets	1,526.6	1,424.4
Property and equipment, net of accumulated depreciation of $274.3 in 2012 and $258.2 in 2011	324.8	326.8
Goodwill	656.3	642.9
Intangible assets, net	249.3	253.6
Deferred tax assets, net	147.3	146.4
Other assets	90.1	82.0
Total assets	2,994.4	2,876.1
Current liabilities:
Accounts payable and accrued liabilities	302.8	452.3
Unrecognized tax benefits		90.0
Current portion of long-term debt	99.4	71.3
Deferred revenue	609.3	520.4
Total current liabilities	1,011.5	1,134.0
Non-current portion of deferred revenue	95.9	97.7
Long-term debt	1,137.4	1,172.5
Deferred tax liabilities, net	60.8	49.6
Unrecognized tax benefits	122.4	115.4
Other liabilities	405.8	404.8
Total liabilities	2,833.8	2,974.0
Contingencies (Note 13)
Redeemable noncontrolling interest	69.4	60.5
Shareholders' equity (deficit):
Preferred stock, par value $.01 per share; 10,000,000 shares authorized; no shares issued and outstanding
Capital surplus	357.0	394.5
Retained earnings	4,350.0	4,176.1
Treasury stock, at cost; 118,210,744 and 120,462,232 shares of common stock at March 31, 2012 and December 31, 2011, respectively	(4,549.0)	(4,635.5)
Accumulated other comprehensive loss	(78.7)	(107.5)
Total Moody's shareholders' equity (deficit)	82.7	(169.0)
Noncontrolling interests	8.5	10.6
Total shareholders' equity (deficit)	91.2	(158.4)
Total liabilities, redeemable noncontrolling interest and shareholders' equity (deficit)	2,994.4	2,876.1
Series Common Stock [Member]
Shareholders' equity (deficit):
Common Stock
Common Stock [Member]
Shareholders' equity (deficit):
Common Stock	$ 3.4	$ 3.4