Proportionaly Consolidated Equity Method Investments (Details) (HGI Energy Holdings, LLC [Member], EXCO/HGI Partnership and the General Partner [Member], USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended
	Jun. 30, 2013	Jun. 30, 2013
HGI Energy Holdings, LLC [Member] | EXCO/HGI Partnership and the General Partner [Member]
Assets
Total current assets	$ 54.2	$ 54.2
Oil and natural gas properties, net	825.4	825.4
Other assets	35.6	35.6
Total assets	915.2	915.2
Liabilities and members' equity
Total current liabilities	43.1	43.1
Total long-term liabilities	402.4	402.4
Total members' equity	469.7	469.7
Total liabilities and members' equity	915.2	915.2
Equity Method Investment, Summarized Financial Information, Income Statement [Abstract]
Revenues	50.7	73.1
Costs and Expenses
Oil and natural gas direct operating costs	24.2	36.0
Selling, acquisition, operating and general expenses	19.7	29.2
Total costs and expenses	43.9	65.2
Operating income	6.8	7.9
Other expense	10.4	(2.7)
Net loss	$ 17.2	$ 5.2