Condensed Consolidating Financial Information - Condensed Consolidating Balance Sheet (Details) - USD ($) $ in Millions | Mar. 31, 2019 | Jan. 01, 2019 | Dec. 31, 2018 | Mar. 31, 2018 | Dec. 31, 2017 |
Current assets: | | | | | |
Cash and cash equivalents | $ 69 | | $ 304 | $ 13 | |
Accounts receivable, net | 435 | | 449 | | |
Accounts receivable from affiliates | 0 | | 0 | | |
Inventories, net | 556 | | 508 | | |
Notes, advance and interest receivable from parent | 0 | | 0 | | |
Notes and interest receivable from affiliates | 0 | | 0 | | |
Other current assets | 58 | | 43 | | |
Total current assets | 1,118 | | 1,304 | | |
Fixed assets, net | 1,492 | | 1,515 | | |
Amortizable intangible assets, net | 51 | $ 51 | 50 | | |
Deferred income tax assets | 872 | | 876 | | |
Operating lease right-of-use assets | 63 | 65 | 0 | | |
Notes receivable from parent | 0 | | 0 | | |
Notes receivable from affiliates | 0 | | 0 | | |
Investments in consolidated subsidiaries and affiliates | 0 | | 0 | | |
Other assets | 206 | | 190 | | |
Total assets | 3,802 | | 3,935 | | |
Current liabilities: | | | | | |
Accounts payable and accrued liabilities | 433 | | 427 | | |
Current portion of long-term debt | 1 | | 223 | | |
Current portion of operating lease liabilities | 7 | 7 | 0 | | |
Accounts payable to affiliates | 0 | | 0 | | |
Notes, advance and interest payable to subsidiaries | 0 | | 0 | | |
Notes and interest payable to affiliates | 0 | | 0 | | |
Total current liabilities | 441 | | 650 | | |
Long-term debt, net of current portion | 422 | | 422 | | |
Notes payable to subsidiaries | 0 | | 0 | | |
Notes payable to affiliates | 0 | | 0 | | |
Pension and other postretirement benefit obligations | 1,247 | | 1,257 | | |
Operating lease liabilities, net of current portion | 59 | 60 | 0 | | |
Other liabilities | 53 | $ 70 | 71 | | |
Total liabilities | 2,222 | | 2,400 | | |
Total equity | 1,580 | | 1,535 | 1,616 | $ 1,600 |
Total liabilities and equity | 3,802 | | 3,935 | | |
Parent [Member] | | | | | |
Current assets: | | | | | |
Cash and cash equivalents | 0 | | 0 | 0 | |
Accounts receivable, net | 1 | | 0 | | |
Accounts receivable from affiliates | 0 | | 0 | | |
Inventories, net | 0 | | 0 | | |
Notes, advance and interest receivable from parent | 0 | | 0 | | |
Notes and interest receivable from affiliates | 0 | | 0 | | |
Other current assets | 0 | | 0 | | |
Total current assets | 1 | | 0 | | |
Fixed assets, net | 0 | | 0 | | |
Amortizable intangible assets, net | 0 | | 0 | | |
Deferred income tax assets | 0 | | 0 | | |
Operating lease right-of-use assets | 0 | | | | |
Notes receivable from parent | 0 | | 0 | | |
Notes receivable from affiliates | 0 | | 0 | | |
Investments in consolidated subsidiaries and affiliates | 4,190 | | 4,119 | | |
Other assets | 0 | | 0 | | |
Total assets | 4,191 | | 4,119 | | |
Current liabilities: | | | | | |
Accounts payable and accrued liabilities | 14 | | 7 | | |
Current portion of long-term debt | 0 | | 222 | | |
Current portion of operating lease liabilities | 0 | | | | |
Accounts payable to affiliates | 603 | | 592 | | |
Notes, advance and interest payable to subsidiaries | 433 | | 422 | | |
Notes and interest payable to affiliates | 0 | | 0 | | |
Total current liabilities | 1,050 | | 1,243 | | |
Long-term debt, net of current portion | 370 | | 370 | | |
Notes payable to subsidiaries | 883 | | 657 | | |
Notes payable to affiliates | 0 | | 0 | | |
Pension and other postretirement benefit obligations | 0 | | 0 | | |
Operating lease liabilities, net of current portion | 0 | | | | |
Other liabilities | 0 | | 6 | | |
Total liabilities | 2,303 | | 2,276 | | |
Total equity | 1,888 | | 1,843 | | |
Total liabilities and equity | 4,191 | | 4,119 | | |
Guarantor Subsidiaries [Member] | | | | | |
Current assets: | | | | | |
Cash and cash equivalents | 62 | | 301 | 8 | |
Accounts receivable, net | 298 | | 301 | | |
Accounts receivable from affiliates | 594 | | 588 | | |
Inventories, net | 212 | | 194 | | |
Notes, advance and interest receivable from parent | 433 | | 422 | | |
Notes and interest receivable from affiliates | 1 | | 4 | | |
Other current assets | 23 | | 15 | | |
Total current assets | 1,623 | | 1,825 | | |
Fixed assets, net | 525 | | 523 | | |
Amortizable intangible assets, net | 3 | | 2 | | |
Deferred income tax assets | 1 | | 1 | | |
Operating lease right-of-use assets | 30 | | | | |
Notes receivable from parent | 883 | | 657 | | |
Notes receivable from affiliates | 109 | | 107 | | |
Investments in consolidated subsidiaries and affiliates | 2,216 | | 2,205 | | |
Other assets | 139 | | 126 | | |
Total assets | 5,529 | | 5,446 | | |
Current liabilities: | | | | | |
Accounts payable and accrued liabilities | 161 | | 170 | | |
Current portion of long-term debt | 1 | | 1 | | |
Current portion of operating lease liabilities | 4 | | | | |
Accounts payable to affiliates | 1,172 | | 1,112 | | |
Notes, advance and interest payable to subsidiaries | 0 | | 0 | | |
Notes and interest payable to affiliates | 0 | | 0 | | |
Total current liabilities | 1,338 | | 1,283 | | |
Long-term debt, net of current portion | 52 | | 52 | | |
Notes payable to subsidiaries | 0 | | 0 | | |
Notes payable to affiliates | 0 | | 0 | | |
Pension and other postretirement benefit obligations | 338 | | 342 | | |
Operating lease liabilities, net of current portion | 27 | | | | |
Other liabilities | 20 | | 21 | | |
Total liabilities | 1,775 | | 1,698 | | |
Total equity | 3,754 | | 3,748 | | |
Total liabilities and equity | 5,529 | | 5,446 | | |
Non-Guarantor Subsidiaries [Member] | | | | | |
Current assets: | | | | | |
Cash and cash equivalents | 7 | | 3 | 5 | |
Accounts receivable, net | 136 | | 148 | | |
Accounts receivable from affiliates | 1,136 | | 1,071 | | |
Inventories, net | 361 | | 327 | | |
Notes, advance and interest receivable from parent | 0 | | 0 | | |
Notes and interest receivable from affiliates | 0 | | 0 | | |
Other current assets | 35 | | 28 | | |
Total current assets | 1,675 | | 1,577 | | |
Fixed assets, net | 967 | | 992 | | |
Amortizable intangible assets, net | 48 | | 48 | | |
Deferred income tax assets | 867 | | 872 | | |
Operating lease right-of-use assets | 33 | | | | |
Notes receivable from parent | 0 | | 0 | | |
Notes receivable from affiliates | 0 | | 0 | | |
Investments in consolidated subsidiaries and affiliates | 0 | | 0 | | |
Other assets | 67 | | 64 | | |
Total assets | 3,657 | | 3,553 | | |
Current liabilities: | | | | | |
Accounts payable and accrued liabilities | 258 | | 250 | | |
Current portion of long-term debt | 0 | | 0 | | |
Current portion of operating lease liabilities | 3 | | | | |
Accounts payable to affiliates | 0 | | 0 | | |
Notes, advance and interest payable to subsidiaries | 0 | | 0 | | |
Notes and interest payable to affiliates | 1 | | 4 | | |
Total current liabilities | 262 | | 254 | | |
Long-term debt, net of current portion | 0 | | 0 | | |
Notes payable to subsidiaries | 0 | | 0 | | |
Notes payable to affiliates | 109 | | 107 | | |
Pension and other postretirement benefit obligations | 909 | | 915 | | |
Operating lease liabilities, net of current portion | 32 | | | | |
Other liabilities | 33 | | 44 | | |
Total liabilities | 1,345 | | 1,320 | | |
Total equity | 2,312 | | 2,233 | | |
Total liabilities and equity | 3,657 | | 3,553 | | |
Consolidating Adjustments [Member] | | | | | |
Current assets: | | | | | |
Cash and cash equivalents | 0 | | 0 | $ 0 | |
Accounts receivable, net | 0 | | 0 | | |
Accounts receivable from affiliates | (1,730) | | (1,659) | | |
Inventories, net | (17) | | (13) | | |
Notes, advance and interest receivable from parent | (433) | | (422) | | |
Notes and interest receivable from affiliates | (1) | | (4) | | |
Other current assets | 0 | | 0 | | |
Total current assets | (2,181) | | (2,098) | | |
Fixed assets, net | 0 | | 0 | | |
Amortizable intangible assets, net | 0 | | 0 | | |
Deferred income tax assets | 4 | | 3 | | |
Operating lease right-of-use assets | 0 | | | | |
Notes receivable from parent | (883) | | (657) | | |
Notes receivable from affiliates | (109) | | (107) | | |
Investments in consolidated subsidiaries and affiliates | (6,406) | | (6,324) | | |
Other assets | 0 | | 0 | | |
Total assets | (9,575) | | (9,183) | | |
Current liabilities: | | | | | |
Accounts payable and accrued liabilities | 0 | | 0 | | |
Current portion of long-term debt | 0 | | 0 | | |
Current portion of operating lease liabilities | 0 | | | | |
Accounts payable to affiliates | (1,775) | | (1,704) | | |
Notes, advance and interest payable to subsidiaries | (433) | | (422) | | |
Notes and interest payable to affiliates | (1) | | (4) | | |
Total current liabilities | (2,209) | | (2,130) | | |
Long-term debt, net of current portion | 0 | | 0 | | |
Notes payable to subsidiaries | (883) | | (657) | | |
Notes payable to affiliates | (109) | | (107) | | |
Pension and other postretirement benefit obligations | 0 | | 0 | | |
Operating lease liabilities, net of current portion | 0 | | | | |
Other liabilities | 0 | | 0 | | |
Total liabilities | (3,201) | | (2,894) | | |
Total equity | (6,374) | | (6,289) | | |
Total liabilities and equity | $ (9,575) | | $ (9,183) | | |