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Accumulated Other Comprehensive Loss - Schedule of Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2017 | Dec. 31, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |
Beginning Balance |  | $ (1,451) |
Net unrealized gain (loss) |  | 114 | $ 1
Ending Balance |  | (597) | (1,451)
Accumulated Translation Adjustment [Member] |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |
Beginning Balance |  | (1,131) | (1,042)
Net unrealized gain (loss) |  | 657 | (109)
Repurchase of shares under normal course issuer bids [note 19] |  | 21 | 20
Ending Balance |  | (453) | (1,131)
Accumulated Net (Loss) Gain from Designated or Qualifying Cash Flow Hedges [Member] |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |
Beginning Balance |  | (135) | (262)
Net unrealized gain (loss) |  | 114 | 1
Reclassification of net loss to net income |  | 60 | 126
Ending Balance |  | 39 | (135)
Accumulated Net Unrealized Loss On Other Long Term Liabilities [Member] |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |
Beginning Balance |  | (185) | (165)
Net unrealized gain (loss) |  | 8 | (29)
Reclassification of net loss to net income |  | 5 | 9
Reclassification of tax effect to retained earnings |  | (11) |
Ending Balance |  | (183) | (185)
Accumulated Net Unrealized Loss on Available-for-Sale investments [Member] |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |
Beginning Balance |  |  | (1)
Reclassification of net loss to net income |  |  | 1
AOCL [Member] |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |
Beginning Balance |  | (1,451) |
Reclassification of tax effect to retained earnings | [1] | (11) |
Ending Balance |  | $ (597) | $ (1,451)
[1] | AOCL is Accumulated Other Comprehensive Loss.

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- Definition Other comprehensive income foreign currency translation adjustment repurchase of shares net of tax. + References No definition available. + Details
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- Definition Other comprehensive income loss net unrealized gain loss on other long term liabilities. + References No definition available. + Details
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- Definition Tax Cuts and Jobs Act of 2017, reclassification from AOCI to retained earnings tax effect. + References No definition available. + Details
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- 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
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- Definition Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=84228862&loc=d3e637-108580 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 14 -URI http://asc.fasb.org/extlink&oid=84228862&loc=d3e681-108580 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 14A -URI http://asc.fasb.org/extlink&oid=84228862&loc=SL7669686-108580 + Details
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- Definition Amount after tax and reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 830 -SubTopic 30 -Section 45 -Paragraph 20 -Subparagraph (b,c) -URI http://asc.fasb.org/extlink&oid=64808268&loc=d3e32211-110900 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 10A -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=84228862&loc=SL7669646-108580 + Details
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