Debt - Schedule of Long-Term Debt (Detail) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Average rate of interest	4.20%
Principal amount outstanding 2020	$ 7,650	$ 7,400
Due in 2021	0
Due after 2021	7,650
Due after 2025	$ 4,250
Average remaining term (in years)	5 years 3 months 18 days
2024 Revolving Credit Facility \| Revolving Credit Facility
Debt Instrument [Line Items]
Range of interest rates	0.00%
Average rate of interest	0.00%
Principal amount outstanding 2020		0
Revolving credit facility	$ 1,500
Notes Payable to Banks \| USD notes
Debt Instrument [Line Items]
Average rate of interest	4.20%
Principal amount outstanding 2020	$ 7,650	7,400
Due in 2021	0
Due after 2021	7,650
Due after 2025	$ 4,250
Average remaining term (in years)	5 years 3 months 18 days
Notes Payable to Banks \| USD notes \| Minimum
Debt Instrument [Line Items]
Range of interest rates	2.70%
Notes Payable to Banks \| USD notes \| Maximum
Debt Instrument [Line Items]
Range of interest rates	5.60%
Bank Borrowings
Debt Instrument [Line Items]
Range of interest rates	0.00%
Average rate of interest	0.00%
Principal amount outstanding 2020		$ 0

Debt and capital lease obligations gross.

No definition available.

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- Definition

Debt instrument face amount long term.

+ References

No definition available.

+ Details

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- Definition

Weighted Average Remaining Term

+ References

No definition available.

+ Details

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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ 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 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ 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 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

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- Definition

Principal amount of long-term debt and capital lease obligation maturing after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

No definition available.

+ Details

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- Definition

Principal amount of long-term debt and capital lease obligation maturing in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

No definition available.

+ Details

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- Definition

Weighted average interest rate of long-term debt outstanding calculated at point in time.

+ References

No definition available.

+ Details

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