Financing Activities (Details) $ in Millions	6 Months Ended
Jun. 30, 2021 USD ($)
Debt Instrument [Line Items]
Debt Instrument, Maturity Date	Jun. 15, 2030
Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Issuance Date	Jun. 09, 2020
Debt Instrument, Interest Rate, Stated Percentage	3.15%
Debt Instrument, Face Amount	$ 600
Long-term Debt, Gross	593
Debt Issuance Costs, Net	$ 5
Senior Notes Due 2021 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.00%
Debt Instrument, Face Amount	$ 400

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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Face (par) amount of debt instrument at time of issuance.

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

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Date the debt instrument was issued, in YYYY-MM-DD format.

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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.

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Date when the debt instrument is scheduled to be fully repaid, in YYYY-MM-DD format.

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Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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