Debt (Details Textuals)	12 Months Ended
Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Debt Instrument [Line Items]
Average commercial paper outstanding	$ 628,000,000	$ 299,000,000
Line of credit maintained	$ 3,500,000,000	3,500,000,000
Ratio of combined earnings and fixed earnings to fixed charges required to maintain availability of credit line	1.25
Fees to maintain credit lines	$ 14,200,000	16,500,000
Total interest paid	2,000,000,000.0	3,400,000,000	$ 2,700,000,000
Short-term Debt [Member]
Debt Instrument [Line Items]
Fees to maintain the secured financing facility	$ 7,700,000	7,700,000
Charge Trust [Member]
Debt Instrument [Line Items]
Specified date face amount of eligible notes issued	Jul. 15, 2022
Face amount of eligible notes from Charge Trust	$ 3,000,000,000.0
Lending Trust [Member]
Debt Instrument [Line Items]
Debt term	3 years
Face amount of eligible notes issued	$ 2,000,000,000.0
Specified date face amount of eligible notes issued	Sep. 15, 2022
Subsidiaries [Member]
Debt Instrument [Line Items]
Line of credit maintained	$ 148,000,000	214,000,000
Amount drawn from committed lines	$ 0	$ 58,000,000

Average Commercial Paper outstanding reported as Short term debt

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- Definition

Debt Instrument, Restrictive Covenants, Combined Earnings, Certain Capital Contributions, And Fixed Charges, To Fixed Charges

+ References

No definition available.

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- Definition

Represents the fees paid to maintain the Company's short-term secured financing facilities.

+ References

No definition available.

+ Details

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- Definition

Represents the face amount of eligible notes, which are secured through a financing facility, and can be issued through a specified date.

+ References

No definition available.

+ Details

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- Definition

Represents the face amount of eligible note that the Company has the right to sell up to at any time through July 15, 2016.

+ References

No definition available.

+ Details

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- Definition

Represents the specified date in which the face amount of eligible notes, which are secured through a financing facility, can be issued.

+ References

No definition available.

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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.

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- Definition

Amount of cash paid for interest, including, but not limited to, capitalized interest and payment to settle zero-coupon bond attributable to accreted interest of debt discount and debt instrument with insignificant coupon interest rate in relation to effective interest rate of borrowing attributable to accreted interest of debt discount; classified as operating and investing activities.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=121583591&loc=d3e4297-108586

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- Definition

Amount of the fee for available but unused credit capacity under the credit 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

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

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- Definition

The carrying value as of the balance sheet date of the current portion of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(13))
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

Reference 2: 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))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

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- Definition

Period between issuance and maturity of long-term debt, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)(2)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

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