Debt (Tables)

9 Months Ended

Sep. 30, 2017

Debt Disclosure [Abstract]

Schedule of Debt

DEBT BALANCE, NET OF UNAMORTIZED ISSUANCE COSTS (in millions)

	September 30, 2017			December 31, 2016
Total debt	$	3,814		$	4,109
Unamortized issuance costs	(48		)	(55		)
Current maturities	(1		)	(1		)
Debt, Net of Current Maturities and Unamortized Issuance Costs	$	3,765		$	4,053

Line of Credit Facility [Line Items]

Schedule of Line of Credit Facilities [Table Text Block]

AVAILABLE CAPACITY UNDER CREDIT FACILITIES (in millions)

	Total Capacity		Amount Borrowed as of September 30, 2017		Outstanding Letters of Credit		Available Capacity as of September 30, 2017		Expiration
Andeavor Logistics Revolving Credit Facility (a)	$	600	$	35	$	—	$	565	January 29, 2021
Andeavor Logistics Dropdown Credit Facility	1,000		—		—		1,000		January 29, 2021
Total Credit Facilities (b)	$	1,600	$	35	$	—	$	1,565

(a) The weighted average interest rate for borrowings under our Revolving Credit Facility was 3.49% at September 30, 2017.

(b) We are allowed to request that the loan availability be increased up to an aggregate of $2.1 billion, subject to receiving increased commitments from the lenders.