Capital Structure - Components of Accumulated Other Comprehensive Loss (Detail) (USD $) In Millions, unless otherwise specified	6 Months Ended
Jun. 30, 2014
Equity [Abstract]
Unrealized gains on available-for-sale securities, beginning balances	$ 7
Unrealized gains on available-for-sale securities, net of income taxes	5
Unrealized gains on available-for-sale securities, ending balances	12
Foreign currency translation adjustments, beginning balances	11
Foreign currency translation adjustments	26
Foreign currency translation adjustments, ending balances	37
Defined benefit plans, beginning balances	(88)
Defined benefit plans, (income) expense reclassified into operations from other comprehensive income	5
Defined benefit plans, ending balances	(83)
Change in fair value of derivative instruments, beginning balances	(187)
Change in fair value of derivative instruments	(19)
Change in fair value of derivatives instruments, (income) expense reclassified into operations from other comprehensive income	41
Change in fair value of derivative instruments, ending balances	(165)
Accumulated other comprehensive income, net of tax, beginning balances	(257)
Unrealized gains on available-for-sale securities, net of income taxes	5
Foreign currency translation adjustments	26
Change in fair value of derivative instruments	(19)
Expense reclassified into operations from other comprehensive income, Total	46
Accumulated other comprehensive income (loss), net of tax, ending balances	$ (199)

Accumulated appreciation or loss, net of tax, in value of the total of available-for-sale securities at the end of an accounting period.

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Accumulated change, net of tax, in accumulated gains and losses from derivative instruments designated and qualifying as the effective portion of cash flow hedges. Includes an entity's share of an equity investee's Increase or Decrease in deferred hedging gains or losses.

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The total of net gain (loss), prior service cost (credit), and transition assets (obligations), as well as minimum pension liability if still remaining, included in accumulated other comprehensive income associated with a defined benefit pension or other postretirement plan(s) because they have yet to be recognized as components of net periodic benefit cost.

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Accumulated adjustment, net of tax, that results from the process of translating subsidiary financial statements and foreign equity investments into the reporting currency from the functional currency of the reporting entity, net of reclassification of realized foreign currency translation gains or losses.

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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.

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Amount after tax and reclassification adjustments, of appreciation (loss) in value of unsold available-for-sale securities. Excludes amounts related to other than temporary impairment (OTTI) loss.

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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.

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Amount after tax of reclassification adjustment from accumulated other comprehensive income of accumulated gain (loss) realized from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's deferred hedging gain (loss).

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Amount after tax of reclassification adjustment from accumulated other comprehensive income (loss) for actuarial gain (loss) related to pension and other postretirement benefit plans.

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Amount after tax of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

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Amount after tax of reclassification adjustments of other comprehensive income (loss).

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