Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2016

Fair Value Disclosures [Abstract]

Schedule Of Carrying Value And Fair Value Measurement Information For Financial Assets And Liabilities

							Fair Value
							Measurements Using:
	Carrying			Total Fair			Level 1		Level 2
	Amount			Value			Inputs		Inputs
	(Millions)
December 31, 2016 assets (liabilities):
Cash equivalents	$	1,542		$	1,542		$	1,298	$	244
Commodity derivatives	$	10		$	10		$	—	$	10
Commodity derivatives	$	(203	)	$	(203	)	$	—	$	(203	)
Interest rate derivatives	$	1		$	1		$	—	$	1
Interest rate derivatives	$	(41	)	$	(41	)	$	—	$	(41	)
Debt	$	(10,154	)	$	(10,760	)	$	—	$	(10,760	)
Installment payment	$	(473	)	$	(477	)	$	—	$	(477	)
Capital lease obligations	$	(7	)	$	(6	)	$	—	$	(6	)
December 31, 2015 assets (liabilities):
Cash equivalents	$	1,871		$	1,871		$	1,471	$	400
Commodity derivatives	$	35		$	35		$	—	$	35
Commodity derivatives	$	(18	)	$	(18	)	$	—	$	(18	)
Interest rate derivatives	$	2		$	2		$	—	$	2
Interest rate derivatives	$	(22	)	$	(22	)	$	—	$	(22	)
Foreign currency derivatives	$	8		$	8		$	—	$	8
Foreign currency derivatives	$	(8	)	$	(8	)	$	—	$	(8	)
Debt	$	(13,032	)	$	(11,927	)	$	—	$	(11,927	)
Capital lease obligations	$	(17	)	$	(16	)	$	—	$	(16	)