Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2021

Fair Value Disclosures [Abstract]

Fair value, assets and liabilities measured on recurring basis

The following tables provide information by level for assets and liabilities that are measured at fair value on a recurring basis.

Description	Fair Value at September 30, 2021		Fair Value Measurements Using Inputs Considered as
(Millions)			Level 1		Level 2		Level 3
Assets:
Available-for-sale:
Marketable securities:
Corporate debt securities	$	—	$	—	$	—	$	—
Commercial paper	501		—		501		—
Certificates of deposit/time deposits	45		—		45		—
U.S. treasury securities	305		305		—		—
U.S. municipal securities	34		—		—		34
Derivative instruments — assets:
Foreign currency forward/option contracts	80		—		80		—
Interest rate contracts	4		—		4		—
Liabilities:
Derivative instruments — liabilities:
Foreign currency forward/option contracts	40		—		40		—

Description	Fair Value at December 31, 2020		Fair Value Measurements Using Inputs Considered as
(Millions)			Level 1		Level 2		Level 3
Assets:
Available-for-sale:
Marketable securities:
Corporate debt securities	$	7	$	—	$	7	$	—
Commercial paper	237		—		237		—
Certificates of deposit/time deposits	31		—		31		—
U.S. treasury securities	125		125		—		—
U.S. municipal securities	34		—		—		34
Derivative instruments — assets:
Foreign currency forward/option contracts	37		—		37		—
Interest rate contracts	7		—		7		—
Liabilities:
Derivative instruments — liabilities:
Foreign currency forward/option contracts	106		—		106		—

Fair value, assets measured on recurring basis, unobservable input reconciliation

The following table provides a reconciliation of the beginning and ending balances of items measured at fair value on a recurring basis in the table above that used significant unobservable inputs (level 3).

Marketable securities — certain U.S. municipal securities only	Three months ended September 30,				Nine months ended September 30,
(Millions)	2021		2020		2021		2020
Beginning balance	$	34	$	37	$	34	$	46
Total gains or losses:
Included in earnings	—		—		—		—
Included in other comprehensive income	—		—		—		—
Purchases and issuances	—		—		—		10
Sales and settlements	—		—		—		(19)
Transfers in and/or out of level 3	—		—		—		—
Ending balance	$	34	$	37	$	34	$	37
Change in unrealized gains or losses for the period included in earnings for securities held at the end of the reporting period	—		—		—		—

Fair value of financial instruments by balance sheet grouping

Information with respect to the carrying amounts and estimated fair values of these financial instruments follow:

	September 30, 2021				December 31, 2020
(Millions)	Carrying Value		Fair Value		Carrying Value		Fair Value
Long-term debt, excluding current portion	$	16,193	$	17,836	$	17,989	$	20,496