XML 66 R52.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Revenues - Revenue by Product Type and Market (Details) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended | 9 Months Ended
--- | --- | --- | ---
Sep. 30, 2018 | Sep. 30, 2017 | Apr. 01, 2017 | Sep. 30, 2017 | Sep. 30, 2018
Successor |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  | $ 1,412.6 | $ 1,477.2 |  | $ 2,735.5 | $ 4,184.7
Successor | Thermal coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  | 1,039.8 | 1,052.4 |  | 1,971.1 | 2,891.5
Successor | Metallurgical coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  | 369.4 | 414.1 |  | 701.9 | 1,251.9
Successor | Other |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  | 3.4 | 10.7 |  | 62.5 | 41.3
Successor | Domestic | Thermal coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  | 769.0 | 806.7 |  | 1,514.5 | 2,213.5
Successor | Export | Thermal coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  | 270.8 | 245.7 |  | 456.6 | 678.0
Successor | Export | Metallurgical coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  | 369.4 | 414.1 |  | 701.9 | 1,251.9
Successor | Operating Segments | Powder River Basin Mining |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  | 373.7 | 420.9 |  | 786.3 | 1,084.5
Successor | Operating Segments | Powder River Basin Mining | Thermal coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  | 373.7 | 420.9 |  | 782.0 | 1,084.4
Successor | Operating Segments | Powder River Basin Mining | Metallurgical coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  | 0.0 | 0.0 |  | 0.0 | 0.0
Successor | Operating Segments | Powder River Basin Mining | Other |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  | 0.0 | 0.0 |  | 4.3 | 0.1
Successor | Operating Segments | Powder River Basin Mining | Domestic | Thermal coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  | 373.7 | 420.9 |  | 782.0 | 1,084.4
Successor | Operating Segments | Powder River Basin Mining | Export | Thermal coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  | 0.0 | 0.0 |  | 0.0 | 0.0
Successor | Operating Segments | Powder River Basin Mining | Export | Metallurgical coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  | 0.0 | 0.0 |  | 0.0 | 0.0
Successor | Operating Segments | Midwestern U.S. Mining |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  | 208.5 | 207.7 |  | 402.6 | 607.7
Successor | Operating Segments | Midwestern U.S. Mining | Thermal coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  | 208.4 | 207.5 |  | 402.3 | 607.5
Successor | Operating Segments | Midwestern U.S. Mining | Metallurgical coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  | 0.0 | 0.0 |  | 0.0 | 0.0
Successor | Operating Segments | Midwestern U.S. Mining | Other |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  | 0.1 | 0.2 |  | 0.3 | 0.2
Successor | Operating Segments | Midwestern U.S. Mining | Domestic | Thermal coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  | 208.4 | 207.1 |  | 401.9 | 606.2
Successor | Operating Segments | Midwestern U.S. Mining | Export | Thermal coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  | 0.0 | 0.4 |  | 0.4 | 1.3
Successor | Operating Segments | Midwestern U.S. Mining | Export | Metallurgical coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  | 0.0 | 0.0 |  | 0.0 | 0.0
Successor | Operating Segments | Western U.S. Mining |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  | 156.1 | 155.7 |  | 281.1 | 439.4
Successor | Operating Segments | Western U.S. Mining | Thermal coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  | 152.6 | 158.3 |  | 282.1 | 426.3
Successor | Operating Segments | Western U.S. Mining | Metallurgical coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  | 0.0 | 0.0 |  | 0.0 | 0.0
Successor | Operating Segments | Western U.S. Mining | Other |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  | 3.5 | (2.6) |  | (1.0) | 13.1
Successor | Operating Segments | Western U.S. Mining | Domestic | Thermal coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  | 149.5 | 147.1 |  | 270.9 | 410.9
Successor | Operating Segments | Western U.S. Mining | Export | Thermal coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  | 3.1 | 11.2 |  | 11.2 | 15.4
Successor | Operating Segments | Western U.S. Mining | Export | Metallurgical coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  | 0.0 | 0.0 |  | 0.0 | 0.0
Successor | Operating Segments | Australian Metallurgical Mining |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  | 370.3 | 415.9 |  | 703.7 | 1,254.0
Successor | Operating Segments | Australian Metallurgical Mining | Thermal coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  | 0.0 | 0.0 |  | 0.0 | 0.0
Successor | Operating Segments | Australian Metallurgical Mining | Metallurgical coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  | 369.4 | 414.1 |  | 701.9 | 1,251.9
Successor | Operating Segments | Australian Metallurgical Mining | Other |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  | 0.9 | 1.8 |  | 1.8 | 2.1
Successor | Operating Segments | Australian Metallurgical Mining | Domestic | Thermal coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  | 0.0 | 0.0 |  | 0.0 | 0.0
Successor | Operating Segments | Australian Metallurgical Mining | Export | Thermal coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  | 0.0 | 0.0 |  | 0.0 | 0.0
Successor | Operating Segments | Australian Metallurgical Mining | Export | Metallurgical coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  | 369.4 | 414.1 |  | 701.9 | 1,251.9
Successor | Operating Segments | Australian Thermal Mining |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  | 305.1 | 265.8 |  | 505.0 | 773.9
Successor | Operating Segments | Australian Thermal Mining | Thermal coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  | 305.1 | 265.7 |  | 504.7 | 773.3
Successor | Operating Segments | Australian Thermal Mining | Metallurgical coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  | 0.0 | 0.0 |  | 0.0 | 0.0
Successor | Operating Segments | Australian Thermal Mining | Other |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  | 0.0 | 0.1 |  | 0.3 | 0.6
Successor | Operating Segments | Australian Thermal Mining | Domestic | Thermal coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  | 37.4 | 31.6 |  | 59.7 | 112.0
Successor | Operating Segments | Australian Thermal Mining | Export | Thermal coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  | 267.7 | 234.1 |  | 445.0 | 661.3
Successor | Operating Segments | Australian Thermal Mining | Export | Metallurgical coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  | 0.0 | 0.0 |  | 0.0 | 0.0
Successor | Corporate, Non-Segment | Trading and Brokerage |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  | 22.6 | 19.4 |  | 24.6 | 52.7
Successor | Corporate, Non-Segment | Trading and Brokerage | Thermal coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  | 0.0 | 0.0 |  | 0.0 | 0.0
Successor | Corporate, Non-Segment | Trading and Brokerage | Metallurgical coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  | 0.0 | 0.0 |  | 0.0 | 0.0
Successor | Corporate, Non-Segment | Trading and Brokerage | Other |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  | 22.6 | 19.4 |  | 24.6 | 52.7
Successor | Corporate, Non-Segment | Trading and Brokerage | Domestic | Thermal coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  | 0.0 | 0.0 |  | 0.0 | 0.0
Successor | Corporate, Non-Segment | Trading and Brokerage | Export | Thermal coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  | 0.0 | 0.0 |  | 0.0 | 0.0
Successor | Corporate, Non-Segment | Trading and Brokerage | Export | Metallurgical coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  | 0.0 | 0.0 |  | 0.0 | 0.0
Successor | Corporate, Non-Segment | Corporate and Other |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues | [1] | (23.7) | (8.2) |  | 32.2 | (27.5)
Successor | Corporate, Non-Segment | Corporate and Other | Thermal coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues | [1] | 0.0 | 0.0 |  | 0.0 | 0.0
Successor | Corporate, Non-Segment | Corporate and Other | Metallurgical coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues | [1] | 0.0 | 0.0 |  | 0.0 | 0.0
Successor | Corporate, Non-Segment | Corporate and Other | Other |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues | [1] | (23.7) | (8.2) |  | 32.2 | (27.5)
Successor | Corporate, Non-Segment | Corporate and Other | Domestic | Thermal coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues | [1] | 0.0 | 0.0 |  | 0.0 | 0.0
Successor | Corporate, Non-Segment | Corporate and Other | Export | Thermal coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues | [1] | 0.0 | 0.0 |  | 0.0 | 0.0
Successor | Corporate, Non-Segment | Corporate and Other | Export | Metallurgical coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues | [1] | $ 0.0 | $ 0.0 |  | $ 0.0 | $ 0.0
Predecessor |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  |  |  | $ 1,326.2 |  |
Predecessor | Thermal coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  |  |  | 945.5 |  |
Predecessor | Metallurgical coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  |  |  | 324.6 |  |
Predecessor | Other |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  |  |  | 56.1 |  |
Predecessor | Domestic | Thermal coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  |  |  | 748.3 |  |
Predecessor | Export | Thermal coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  |  |  | 197.2 |  |
Predecessor | Export | Metallurgical coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  |  |  | 324.6 |  |
Predecessor | Operating Segments | Powder River Basin Mining |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  |  |  | 394.3 |  |
Predecessor | Operating Segments | Powder River Basin Mining | Thermal coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  |  |  | 394.3 |  |
Predecessor | Operating Segments | Powder River Basin Mining | Metallurgical coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  |  |  | 0.0 |  |
Predecessor | Operating Segments | Powder River Basin Mining | Other |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  |  |  | 0.0 |  |
Predecessor | Operating Segments | Powder River Basin Mining | Domestic | Thermal coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  |  |  | 394.3 |  |
Predecessor | Operating Segments | Powder River Basin Mining | Export | Thermal coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  |  |  | 0.0 |  |
Predecessor | Operating Segments | Powder River Basin Mining | Export | Metallurgical coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  |  |  | 0.0 |  |
Predecessor | Operating Segments | Midwestern U.S. Mining |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  |  |  | 193.2 |  |
Predecessor | Operating Segments | Midwestern U.S. Mining | Thermal coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  |  |  | 193.2 |  |
Predecessor | Operating Segments | Midwestern U.S. Mining | Metallurgical coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  |  |  | 0.0 |  |
Predecessor | Operating Segments | Midwestern U.S. Mining | Other |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  |  |  | 0.0 |  |
Predecessor | Operating Segments | Midwestern U.S. Mining | Domestic | Thermal coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  |  |  | 193.2 |  |
Predecessor | Operating Segments | Midwestern U.S. Mining | Export | Thermal coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  |  |  | 0.0 |  |
Predecessor | Operating Segments | Midwestern U.S. Mining | Export | Metallurgical coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  |  |  | 0.0 |  |
Predecessor | Operating Segments | Western U.S. Mining |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  |  |  | 149.7 |  |
Predecessor | Operating Segments | Western U.S. Mining | Thermal coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  |  |  | 133.5 |  |
Predecessor | Operating Segments | Western U.S. Mining | Metallurgical coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  |  |  | 0.0 |  |
Predecessor | Operating Segments | Western U.S. Mining | Other |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  |  |  | 16.2 |  |
Predecessor | Operating Segments | Western U.S. Mining | Domestic | Thermal coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  |  |  | 133.5 |  |
Predecessor | Operating Segments | Western U.S. Mining | Export | Thermal coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  |  |  | 0.0 |  |
Predecessor | Operating Segments | Western U.S. Mining | Export | Metallurgical coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  |  |  | 0.0 |  |
Predecessor | Operating Segments | Australian Metallurgical Mining |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  |  |  | 328.9 |  |
Predecessor | Operating Segments | Australian Metallurgical Mining | Thermal coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  |  |  | 0.0 |  |
Predecessor | Operating Segments | Australian Metallurgical Mining | Metallurgical coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  |  |  | 324.6 |  |
Predecessor | Operating Segments | Australian Metallurgical Mining | Other |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  |  |  | 4.3 |  |
Predecessor | Operating Segments | Australian Metallurgical Mining | Domestic | Thermal coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  |  |  | 0.0 |  |
Predecessor | Operating Segments | Australian Metallurgical Mining | Export | Thermal coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  |  |  | 0.0 |  |
Predecessor | Operating Segments | Australian Metallurgical Mining | Export | Metallurgical coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  |  |  | 324.6 |  |
Predecessor | Operating Segments | Australian Thermal Mining |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  |  |  | 224.8 |  |
Predecessor | Operating Segments | Australian Thermal Mining | Thermal coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  |  |  | 224.5 |  |
Predecessor | Operating Segments | Australian Thermal Mining | Metallurgical coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  |  |  | 0.0 |  |
Predecessor | Operating Segments | Australian Thermal Mining | Other |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  |  |  | 0.3 |  |
Predecessor | Operating Segments | Australian Thermal Mining | Domestic | Thermal coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  |  |  | 27.3 |  |
Predecessor | Operating Segments | Australian Thermal Mining | Export | Thermal coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  |  |  | 197.2 |  |
Predecessor | Operating Segments | Australian Thermal Mining | Export | Metallurgical coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  |  |  | 0.0 |  |
Predecessor | Corporate, Non-Segment | Trading and Brokerage |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  |  |  | 15.0 |  |
Predecessor | Corporate, Non-Segment | Trading and Brokerage | Thermal coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  |  |  | 0.0 |  |
Predecessor | Corporate, Non-Segment | Trading and Brokerage | Metallurgical coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  |  |  | 0.0 |  |
Predecessor | Corporate, Non-Segment | Trading and Brokerage | Other |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  |  |  | 15.0 |  |
Predecessor | Corporate, Non-Segment | Trading and Brokerage | Domestic | Thermal coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  |  |  | 0.0 |  |
Predecessor | Corporate, Non-Segment | Trading and Brokerage | Export | Thermal coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  |  |  | 0.0 |  |
Predecessor | Corporate, Non-Segment | Trading and Brokerage | Export | Metallurgical coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues |  |  |  | 0.0 |  |
Predecessor | Corporate, Non-Segment | Corporate and Other |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues | [1] |  |  | 20.3 |  |
Predecessor | Corporate, Non-Segment | Corporate and Other | Thermal coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues | [1] |  |  | 0.0 |  |
Predecessor | Corporate, Non-Segment | Corporate and Other | Metallurgical coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues | [1] |  |  | 0.0 |  |
Predecessor | Corporate, Non-Segment | Corporate and Other | Other |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues | [1] |  |  | 20.3 |  |
Predecessor | Corporate, Non-Segment | Corporate and Other | Domestic | Thermal coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues | [1] |  |  | 0.0 |  |
Predecessor | Corporate, Non-Segment | Corporate and Other | Export | Thermal coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues | [1] |  |  | 0.0 |  |
Predecessor | Corporate, Non-Segment | Corporate and Other | Export | Metallurgical coal |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |
Revenues | [1] |  |  | $ 0.0 |  |
[1] | Corporate and Other revenue includes unrealized gains and losses related to mark-to-market activity from economic hedge activities intended to hedge future coal sales. Such net unrealized losses were $26.8 million and $10.8 million during the three months ended September 30, 2018 and 2017, respectively, and $36.3 million and $1.4 million during the nine months ended September 30, 2018 and the period April 2 through September 30, 2017, respectively. During the period January 1 through April 1, 2017, such net unrealized gains were $16.6 million. When such gains and losses are realized in connection with recognition of the underlying transaction, they are reclassified to realized gains and losses and are then reflected in Trading and Brokerage revenue (realized losses of $11.6 million and $12.3 million during the three months ended September 30, 2018 and 2017, respectively, and $41.1 million, $20.0 million and $11.1 million during the nine months ended September 30, 2018 and the periods April 2 through September 30, 2017 and January 1 through April 1, 2017, respectively). At September 30, 2018 and December 31, 2017, the financial contracts’ fair values resulted in net liabilities, excluding margin, of $75.2 million and $38.9 million, respectively.

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_DisaggregationOfRevenueLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.1) -URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688 + Details
Name: | us-gaap_Revenues
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_StatementScenarioAxis=us-gaap_SuccessorMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ProductOrServiceAxis=btu_ThermalCoalMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ProductOrServiceAxis=btu_MetallurgicalCoalMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ProductOrServiceAxis=us-gaap_ProductMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_GeographicDistributionAxis=us-gaap_DomesticDestinationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_GeographicDistributionAxis=us-gaap_GeographicDistributionForeignMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ConsolidationItemsAxis=us-gaap_OperatingSegmentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=btu_PowderRiverBasinMiningMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=btu_MidwesternUSMiningMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=btu_WesternUSMiningMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=btu_AustralianMetallurgicalMiningMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=btu_AustralianThermalMiningMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ConsolidationItemsAxis=us-gaap_CorporateNonSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=btu_TradingAndBrokerageMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=us-gaap_CorporateAndOtherMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementScenarioAxis=us-gaap_PredecessorMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |