Basis of Preparation (Details)	3 Months Ended
	Mar. 31, 2013
Basis of Preparation [Abstract]
Minimum percentage of ownership considered for consolidation (in hundredths)	50.00%
Minimum percentage of ownership considered for equity method of accounting for investments (in hundredths)	20.00%
Maximum percentage of ownership considered for equity method of accounting for investments (in hundredths)	50.00%
Maximum percentage of ownership considered for cost method of accounting for investments (in hundredths)	20.00%