Earnings Per Share (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Amount attributable to The McGraw-Hill Companies, Inc. common shareholders:
Income from continuing operations	$ 314	$ 367	$ 652	$ 698
Loss from discontinued operations, net of tax	0	(1)	0	(2)
Net income attributable to The McGraw-Hill Companies, Inc.	$ 314	$ 366	$ 652	$ 696
Basic weighted-average number of common shares outstanding	278.7	297.8	278.8	302.2
Effect of stock options and other dilutive securities	5.9	5.8	5.8	5.2
Diluted weighted-average number of common shares outstanding	284.6	303.6	284.6	307.4
Basic EPS:
Income from continuing operations	$ 1.13	$ 1.23	$ 2.34	$ 2.31
Loss from discontinued operations, net of tax	$ 0.00	$ 0.00	$ 0.00	$ 0
Net income	$ 1.13	$ 1.23	$ 2.34	$ 2.31
Diluted EPS:
Income from continuing operations	$ 1.10	$ 1.21	$ 2.29	$ 2.27
Loss from discontinued operations, net of tax	$ 0.00	$ 0.00	$ 0.00	$ 0
Net income	$ 1.10	$ 1.21	$ 2.29	$ 2.27
Restricted Stock [Member]
Common Shares Outstanding (Textual) [Abstract]
Outstanding shares not included in the computation of diluted earnings per share for both restricted stock and stock options			2.7	1.6
Stock Options [Member]
Common Shares Outstanding (Textual) [Abstract]
Outstanding shares not included in the computation of diluted earnings per share for both restricted stock and stock options	3.2	9.9	3.9	10.2