Growth and Value Plan (Details) (USD $) In Millions, except Share data, unless otherwise specified	9 Months Ended	12 Months Ended
Sep. 30, 2012	Sep. 30, 2012
Spinoff and Related Activities Disclosure [Abstract]
Spin-off distribution ratio, spinnee shares to be eceived	1
Spinoff distribution ratio, spinnor shares held	3
Growth and value plan, cost incurred to date		$ 184

Spinoff and Related Activities, Costs Incurred to Date

No definition available.

Name:	mhp_SpinoffAndRelatedActivitiesCostsIncurredToDate
Namespace Prefix:	mhp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration