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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Nominal or face amount used to calculate payments on the derivative asset.

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The carrying value as of the balance sheet date of the current and noncurrent portions 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.

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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.

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Amount, after tax and before reclassification, of gain (loss) from derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness.

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Debt and Credit Agreements - Narrative (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	Jul. 09, 2020	Apr. 29, 2020
Commercial Paper
Line of Credit Facility
Maximum borrowing capacity of credit facility	$ 1,000,000,000		$ 1,000,000,000
Borrowings outstanding	0		0
3.25% Notes Due 2027
Line of Credit Facility
Debt issued						$ 850,000,000
Debt interest rate						3.25%
Unsecured Revolving Credit Facility Expiring March 2024 \| Credit Facility
Line of Credit Facility
Maximum borrowing capacity of credit facility	1,200,000,000		1,200,000,000
Borrowings outstanding	0		0
Designated as Hedging Instrument \| Interest Rate Swap \| Cash Flow Hedge
Line of Credit Facility
Aggregate notional value of interest forward interest rate swap	116,000,000		116,000,000		$ 80,000,000	$ 500,000,000	$ 250,000,000
Unrealized gains recorded net of tax in other comprehensive income related to hedge	$ 7,000,000	$ 25,000,000	$ 28,000,000	$ 34,000,000