Financial Instruments (Tables)

6 Months Ended

Jun. 30, 2018

The net carrying and estimated fair values of our financial instruments by class at June 30, 2018 and December 31, 2017 were as follows:



	June 30, 2018				December 31, 2017
	Net Carrying Amount		Fair Value		Net Carrying Amount		Fair Value
	(Millions)
Long-term debt (including current maturities)	$	1,385	$	1,335	$	1,361	$	1,398
Equity swap agreement and foreign currency forward contracts:
Asset derivative contracts (a)	2		2		4		4

(a) All derivatives are categorized within Level 2 of the fair value hierarchy.

Summarization for Foreign Currency Forward Purchase and Sale Contracts

The following table summarizes by major currency the notional amounts for foreign currency forward purchase and sale contracts as of June 30, 2018 (all of which mature in 2018):



		Notional Amount in Foreign Currency
		(Millions)
Canadian dollars	—Sell	(2	)
Chinese yuan	—Purchase	3
U.S. dollars	—Purchase	2