Pension and Other Postretirement Healthcare Benefits - Summary of Expected Benefit Payments (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2013	$ 29
2014	28
2015	27
2016	27
2017	27
2018- 2022	131
Retirement Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2013	32
2014	31
2015	31
2016	30
2017	31
2018- 2022	153
Postretirement healthcare plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2013	1
2014	1
2015	1
2016	1
2017	1
2018- 2022	$ 6

Amount of benefits expected to be paid in the five fiscal years after the fifth fiscal year following the latest fiscal year from a defined benefit plan.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (f)

-URI http://asc.fasb.org/extlink&oid=21915506&loc=d3e1928-114920

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Amount of benefits expected to be paid in the next fiscal year following the latest fiscal year from a defined benefit plan.

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Amount of benefits expected to be paid in the fifth fiscal year following the latest fiscal year from a defined benefit plan.

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Amount of benefits expected to be paid in the fourth fiscal year following the latest fiscal year from a defined benefit plan.

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Amount of benefits expected to be paid in the third fiscal year following the latest fiscal year from a defined benefit plan.

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Amount of benefits expected to be paid in the second fiscal year following the latest fiscal year from a defined benefit plan.

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