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Debt - Narrative (Detail) - USD ($) | 3 Months Ended |
--- | --- | ---
Mar. 31, 2018 | Mar. 31, 2017 | Dec. 31, 2017
Debt Instrument [Line Items] |  |  |
Interest expense for premium paid for early redemption of notes in excess of carrying value | $ 114,000,000 | $ 115,000,000 |
5.72% Notes, due 2019 |  |  |
Debt Instrument [Line Items] |  |  |
Long-term debt, interest rate | 5.72% |  |
Long-term debt |  |  | $ 500,000,000
Redemption amount | $ 518,000,000 |  |
Loss on prepayment of debt redemption | $ 19,000,000 |  |

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- Definition Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 50 -Section 40 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=49170532&loc=d3e12317-112629 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 50 -Section 40 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=49170532&loc=d3e12355-112629 + Details
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