Marketable Securities (Tables)

3 Months Ended

Mar. 31, 2021

Marketable Securities.

Schedule of marketable securities

(Millions)	March 31, 2021		December 31, 2020
Corporate debt securities	$	7	$	7
Commercial paper		384		237
Certificates of deposit/time deposits		7		31
U.S. treasury securities		100		125
U.S. municipal securities		3		4
Current marketable securities	$	501	$	404
U.S. municipal securities	$	31	$	30
Non-current marketable securities	$	31	$	30
Total marketable securities	$	532	$	434

Schedule of marketable securities by contractual maturity

(Millions)	March 31, 2021
Due in one year or less	$	501
Due after one year through five years		15
Due after five years through ten years		16
Total marketable securities	$	532