Supplemental Guarantor/Non-Guarantor Financial Information Supplemental DND financial information details 5 (Details) - USD ($) $ in Millions	Dec. 31, 2016	Apr. 12, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Cash and cash equivalents	$ 872.3	$ 652.1	$ 261.3	$ 298.0	$ 444.0
Restricted Cash and Investments, Current	54.3		0.0
Accounts receivable, net	473.0		228.8
Receivables from affiliates, net	0.0		0.0
Inventory, Net	203.7		307.8
Assets From Coal Trading Activities, Net	0.7		23.5
Deferred Tax Assets, Net of Valuation Allowance, Current	0.0		53.5
Other current assets	486.6		447.6
Assets, Current	2,090.6		1,322.5
Property, Plant and Equipment, Net	8,776.7		9,258.5	10,577.3
Deferred income taxes	0.0		2.2
Other Assets, Noncurrent	910.4		363.7
Notes Receivable, Related Parties	0.0		0.0
Total assets	11,777.7		10,946.9	13,191.1
Long-term Debt and Capital Lease Obligations, Current	20.2		5,874.9
Payables to affiliates, net	0.0		0.0
Taxes Payable, Current	6.2
Liabilities from coal trading activities, net	1.2		15.6
Accounts Payable and Other Accrued Liabilities, Current	984.2		1,442.5
Liabilities, Current	1,011.8		7,336.8
Deferred Tax Liabilities, Net, Noncurrent	173.9		235.9	0.0
Notes Payable, Related Parties, Noncurrent	0.0		0.0
Other noncurrent liabilities	1,970.3		2,256.2
Total liabilities not subject to compromise	3,156.0		10,195.2
Liabilities Subject to Compromise	8,440.2		0.0
Liabilities	11,596.2		10,195.2
Peabody Energy Corporation's stockholders' equity	173.9		750.1
Stockholders' Equity Attributable to Noncontrolling Interest	7.6		1.6
Total stockholders' equity	181.5		751.7	2,529.0	3,696.6
Liabilities and Equity	11,777.7		10,946.9
Non-Debtor Subsidiaries [Member]
Cash and cash equivalents	477.8	543.6
Restricted Cash and Investments, Current	40.5
Accounts receivable, net	467.8
Receivables from affiliates, net	0.0
Inventory, Net	107.4
Assets From Coal Trading Activities, Net	0.0
Deferred Tax Assets, Net of Valuation Allowance, Current	0.0
Other current assets	416.2
Assets, Current	1,509.7
Property, Plant and Equipment, Net	3,906.5
Deferred income taxes	0.0
Other Assets, Noncurrent	596.7
Notes Receivable, Related Parties	0.0
Total assets	6,012.9
Long-term Debt and Capital Lease Obligations, Current	0.9
Payables to affiliates, net	226.9
Taxes Payable, Current	7.8
Liabilities from coal trading activities, net	1.3
Accounts Payable and Other Accrued Liabilities, Current	442.5
Liabilities, Current	679.4
Deferred Tax Liabilities, Net, Noncurrent	161.8
Notes Payable, Related Parties, Noncurrent	1,036.3
Other noncurrent liabilities	321.5
Total liabilities not subject to compromise	2,199.0
Liabilities Subject to Compromise	0.0
Liabilities	2,199.0
Peabody Energy Corporation's stockholders' equity	3,806.3
Stockholders' Equity Attributable to Noncontrolling Interest	7.6
Total stockholders' equity	3,813.9
Liabilities and Equity	6,012.9
Debtor Subsidiaries [Member]
Cash and cash equivalents	394.5	$ 108.5
Restricted Cash and Investments, Current	13.8
Accounts receivable, net	5.2
Receivables from affiliates, net	226.9
Inventory, Net	96.3
Assets From Coal Trading Activities, Net	0.9
Deferred Tax Assets, Net of Valuation Allowance, Current	0.0
Other current assets	72.0
Assets, Current	809.6
Property, Plant and Equipment, Net	4,870.2
Deferred income taxes	0.0
Other Assets, Noncurrent	4,125.9
Notes Receivable, Related Parties	1,036.3
Total assets	10,842.0
Long-term Debt and Capital Lease Obligations, Current	19.3
Payables to affiliates, net	0.0
Taxes Payable, Current	0.0
Liabilities from coal trading activities, net	0.1
Accounts Payable and Other Accrued Liabilities, Current	541.7
Liabilities, Current	561.1
Deferred Tax Liabilities, Net, Noncurrent	12.1
Notes Payable, Related Parties, Noncurrent	0.0
Other noncurrent liabilities	1,648.8
Total liabilities not subject to compromise	2,222.0
Liabilities Subject to Compromise	8,440.2
Liabilities	10,662.2
Peabody Energy Corporation's stockholders' equity	179.8
Stockholders' Equity Attributable to Noncontrolling Interest	0.0
Total stockholders' equity	179.8
Liabilities and Equity	10,842.0
Noncontrolling Interest [Member]
Total stockholders' equity	$ 7.6		$ 1.6	$ 1.7	$ 39.2