Condensed Consolidated Balance Sheets (USD $) In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Current assets
Cash and cash equivalents	$ 551.3	$ 558.8
Accounts receivable, net of allowance for doubtful accounts of $4.2 at September 30, 2013 and $13.7 at December 31, 2012	701.7	737.8
Inventories	563.2	548.4
Assets from coal trading activities, net	43.0	52.4
Deferred income taxes	69.5	56.4
Other current assets	359.1	621.7
Total current assets	2,287.8	2,575.5
Property, plant, equipment and mine development
Land and coal interests	11,051.4	10,947.7
Buildings and improvements	1,904.8	1,784.5
Machinery and equipment	2,617.2	2,699.0
Less: accumulated depreciation, depletion and amortization	(4,125.1)	(3,629.5)
Property, plant, equipment and mine development, net	11,448.3	11,801.7
Investments and other assets	1,154.8	1,431.8
Total assets	14,890.9	15,809.0
Current liabilities
Current maturities of long-term debt	34.2	47.8
Liabilities from coal trading activities, net	10.0	19.4
Accounts payable and accrued expenses	1,615.3	1,606.9
Total current liabilities	1,659.5	1,674.1
Long-term debt, less current maturities	5,973.3	6,205.1
Deferred income taxes	237.0	577.3
Asset retirement obligations	717.3	687.5
Accrued postretirement benefit costs	954.0	960.7
Other noncurrent liabilities	814.9	765.5
Total liabilities	10,356.0	10,870.2
Stockholders' equity
Additional paid-in capital	2,328.0	2,286.3
Treasury stock, at cost: 13.8 shares as of September 30, 2013 and 13.7 shares as of December 31, 2012	(464.5)	(461.6)
Retained earnings	3,038.4	3,066.4
Accumulated other comprehensive (loss) income	(405.9)	11.0
Peabody Energy Corporation's stockholders' equity	4,498.8	4,904.9
Noncontrolling interests	36.1	33.9
Total stockholders' equity	4,534.9	4,938.8
Total liabilities and stockholders' equity	14,890.9	15,809.0
Preferred Stock [Member]
Stockholders' equity
Preferred Stock	0	0
Perpetual Preferred Stock
Stockholders' equity
Preferred Stock	0	0
Series Common Stock
Stockholders' equity
Common Stock	0	0
Common Stock [Member]
Stockholders' equity
Common Stock	$ 2.8	$ 2.8