Employee Benefit Plans (Narrative) (Detail) - USD ($) shares in Millions, $ in Millions	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020
Deferred compensation arrangements [Abstract]
Deferred compensation plan, maximum deferral percentage	100.00%
Assets held-in-trust	$ 134	$ 116
Unfunded liabilities	$ 153	$ 131
Defined benefit pension plans and defined benefit postretirement plans disclosure [Abstract]
Executive and management supplemental benefit plans compensation period	5 years
Savings Plan
Deferred compensation arrangements [Abstract]
Common stock, outstanding	1.7	1.8
Percentage of plan shares in total shares outstanding	1.60%	1.70%
Unfunded Supplemental Benefit Plans
Defined benefit pension plans and defined benefit postretirement plans disclosure [Abstract]
Cash contribution to plans during the next 12 months	$ 16
Unfunded Supplemental Benefit Plans \| Maximum
Defined benefit pension plans and defined benefit postretirement plans disclosure [Abstract]
Maximum benefit rate of final average compensation under non qualified plan	30.00%
Unfunded Supplemental Benefit Plans \| Minimum
Defined benefit pension plans and defined benefit postretirement plans disclosure [Abstract]
Maximum benefit rate of final average compensation under non qualified plan	15.00%
Defined Benefit Pension And Supplemental Benefit Plans
Defined benefit pension plans and defined benefit postretirement plans disclosure [Abstract]
Net actuarial loss expected to be amortized from accumulated comprehensive income/loss into net periodic loss in next fiscal year	$ 6

Maximum salary deferral rate for employees under the deferred compensation plan.

No definition available.

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- Definition

The amount of time over which the average compensation is calculated for purposes of the defined benefit plan.

+ References

No definition available.

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- Definition

Defined Benefits Pension Plans And Defined Benefits Postretirement Plans Disclosure [Abstract]

+ References

No definition available.

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- Definition

Defined contribution plan, number of shares of equity securities issued by employer and related parties included in plan assets.

+ References

No definition available.

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- Definition

Defined contribution plan, number of shares of equity securities issued by employer and related parties included in plan assets as a percentage of total employer shares outstanding.

+ References

No definition available.

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- Definition

Maximum benefit rate of final average compensation under the nonqualified plan.

+ References

No definition available.

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- References

No definition available.

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- Definition

Aggregate carrying value as of the balance sheet date of the liabilities for all deferred compensation arrangements. Represents currently earned compensation under compensation arrangements that is not actually paid until a later date.

+ References

No definition available.

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- Definition

Carrying amount as of the balance sheet date of assets held under deferred compensation agreements.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.17)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

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- Definition

Amount included in accumulated other comprehensive income (loss) for gain (loss) of defined benefit plan expected to be recognized in net periodic benefit (cost) credit for fiscal year following most recent annual statement of financial position.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (s)
-URI http://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920

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- Definition

Amount of contribution expected to be received by defined benefit plan from employer in next fiscal year following current fiscal year.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 55
-Paragraph 18
-URI http://asc.fasb.org/extlink&oid=123450688&loc=d3e4587-114921

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