Acquisitions and Divestitures (Narrative) (Details) (USD $) Share data in Millions, unless otherwise specified	3 Months Ended		9 Months Ended		1 Months Ended		9 Months Ended	0 Months Ended	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Aug. 31, 2013 CRISIL Limited	Jun. 30, 2013 CRISIL Limited	Sep. 30, 2013 CRISIL Limited	Mar. 22, 2013 MHE	Sep. 30, 2013 MHE	Aug. 27, 2013 CRISIL Limited India Index Services & Products Ltd
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Offer to purchase additional equity percent						22.23%
Shares acquired					11
Percent of total shares aquired					15.07%
Consideration for shares					$ 214,000,000
Ownership percentage						52.77%	67.84%
Contingent purchase price payment			12,000,000	0			12,000,000
Pre-tax gain on dispositions	24,000,000
Percent of equity interest sold										49.00%
After-tax gain on sale of business	(20,000,000)	0	592,000,000	0					592,000,000
Cash proceeds from sale of business								$ 2,400,000,000