Employee Retirement Plans - Changes in Projected Benefit Obligation (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Changes in fair value of plan assets:
Company contributions	$ 36
Non-Qualified Plans [Member]
Changes in projected benefit obligation:
Beginning Balance	174	163
Service cost
Interest cost	7	8	9
Actuarial loss (gain), net	11	13
Benefit payments	(11)	(10)
Ending Balance	181	174	163
Changes in fair value of plan assets:
Company contributions	11	10
Benefit payments	(11)	(10)
Funded status at December 31:	(181)	(174)
Qualified Plans [Member]
Changes in projected benefit obligation:
Beginning Balance	943	868
Service cost	2	2	3
Interest cost	42	44	45
Actuarial loss (gain), net	100	70
Foreign currency exchange	9	(2)
Benefit payments	(40)	(39)
Ending Balance	1,056	943	868
Changes in fair value of plan assets:
Beginning Balance	504	509
Actual return on plan assets	75	(1)
Foreign currency exchange	4
Company contributions	55	38
Expenses, other	(4)	(3)
Benefit payments	(40)	(39)
Ending Balance	594	504	509
Funded status at December 31:	$ (462)	$ (439)

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Other Expenses Related To Changes In Fair Value Of Plan Assets

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The difference between fair value of plan assets at the end of the period and the fair value at the beginning of the period, adjusted for contributions and payments of benefits during the period, and after adjusting for taxes and other expenses, as applicable.

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-Glossary Actual Return on Plan Assets (Component of Net Periodic Postretirement Benefit Cost)

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Amount of gain (loss) from a decision to temporarily deviate from the substantive plan, or from a change in benefit obligation or plan asset value from changes in actuarial assumptions, for example, but not limited to, interest, mortality, employee turnover or salary scale.

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1) For defined benefit pension plans, the benefit obligation is the projected benefit obligation, which is the actuarial present value as of a date of all benefits attributed by the pension benefit formula to employee service rendered prior to that date. 2) For other postretirement defined benefit plans, the benefit obligation is the accumulated postretirement benefit obligation, which is the actuarial present value of benefits attributed to employee service rendered to a particular date.

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The amount of payments made for which participants are entitled under a pension plan, including pension benefits, death benefits, and benefits due on termination of employment. Also includes payments made under a postretirement benefit plan, including prescription drug benefits, health care benefits, life insurance benefits, and legal, educational and advisory services. This item represents a periodic decrease to the plan obligations and a decrease to plan assets.

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The increase in the fair value of plan assets from contributions made by the employer.

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Assets, usually stocks, bonds, and other investments, that have been segregated and restricted (usually in a trust) to provide benefits, at their fair value as of the measurement date. Plan assets include amounts contributed by the employer (and by employees for a contributory plan) and amounts earned from investing the contributions, less benefits paid. If a plan has liabilities other than for benefits, those non-benefit obligations may be considered as reductions of plan assets.

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Amount of gain (loss) from foreign currency exchange rate changes for benefit obligation for plans of a foreign operation whose functional currency is not the reporting currency.

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The amount of increase or decrease in plan assets attributed to foreign currency changes. The effects of foreign currency exchange rate changes that are to be disclosed are those applicable to plans of a foreign operation whose functional currency is not the reporting currency.

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The funded status is measured as the difference between the fair value of plan assets and the benefit obligation. Will normally be the same as the net Defined Benefit Plan, Amounts Recognized in Balance Sheet, Total.

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The increase in a defined benefit pension plan's projected benefit obligation or a defined benefit postretirement plan's accumulated postretirement benefit obligation due to the passage of time.

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The actuarial present value of benefits attributed by the pension benefit formula to services rendered by employees during the period. The portion of the expected postretirement benefit obligation attributed to employee service during the period. The service cost component is a portion of the benefit obligation and is unaffected by the funded status of the plan.

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