Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2017

Fair Value Disclosures [Abstract]

Fair Values of Certain Financial Liabilities and Other Financial Instruments

The fair value of certain financial liabilities is shown below (in millions):

	September 30, 2017				December 31, 2016
	Carrying Amount		Fair Value		Carrying Amount		Fair Value
Financial liabilities
Senior notes (Level 1)	$	2,777	$	2,952	$	2,380	$	2,477
Credit facility (Level 2)		1,184		1,193		1,206		1,211
Mortgage debt and other, excluding capital leases       (Level2)		—		—		62		62