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Pension Plans and Postretirement Benefits - Plan Asset Allocations by Asset Category (Detail)	Dec. 31, 2021	Dec. 31, 2020
UNITED STATES | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Total	100.00%	100.00%
UNITED STATES | Pension Plan | Commingled and Mutual Funds
Defined Benefit Plan Disclosure [Line Items]
Total	29.00%	29.00%
UNITED STATES | Pension Plan | U.S. Government Securities
Defined Benefit Plan Disclosure [Line Items]
Total	32.00%	28.00%
UNITED STATES | Pension Plan | Fixed Income (excluding U.S. Government Securities)
Defined Benefit Plan Disclosure [Line Items]
Total	11.00%	18.00%
UNITED STATES | Pension Plan | Diversified Credit
Defined Benefit Plan Disclosure [Line Items]
Total	11.00%	11.00%
UNITED STATES | Pension Plan | Real Estate
Defined Benefit Plan Disclosure [Line Items]
Total	11.00%	7.00%
UNITED STATES | Pension Plan | Partnerships with Security Holdings
Defined Benefit Plan Disclosure [Line Items]
Total	4.00%	4.00%
UNITED STATES | Pension Plan | Other
Defined Benefit Plan Disclosure [Line Items]
Total	2.00%	3.00%
CANADA | Other Benefits
Defined Benefit Plan Disclosure [Line Items]
Total	100.00%	100.00%
CANADA | Other Benefits | Equity Securities and Commingled Mutual Funds
Defined Benefit Plan Disclosure [Line Items]
Total	11.00%	0.00%
CANADA | Other Benefits | Fixed Income
Defined Benefit Plan Disclosure [Line Items]
Total	20.00%	98.00%
CANADA | Other Benefits | Other
Defined Benefit Plan Disclosure [Line Items]
Total	69.00%	2.00%

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- Definition

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+ References

No definition available.

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- Definition

Percentage of actual investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one plan.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (d)(i)
-URI http://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920

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