Income Taxes (Tables)

9 Months Ended

Sep. 30, 2016

Income Tax Disclosure [Abstract]

Schedule Of Effective Income Tax Rate Reconciliation

	Three Months Ended September 30,						Nine Months Ended September 30,
	2016			2015			2016			2015
	(Millions)
Current income tax expense (benefit)	$	85		$	(6	)	$	72		$	(87	)
Deferred income tax expense (benefit)		86			(1,708	)		(300	)		(5,348	)
Total income tax expense (benefit)	$	171		$	(1,714	)	$	(228	)	$	(5,435	)
U.S. statutory income tax rate		35	%		35	%		35	%		35	%
Deferred tax asset valuation allowance		(35	%)		0	%		(20	%)		0	%
Non-deductible goodwill and intangible impairment		6	%		(5	%)		(9	%)		(2	%)
Change in unrecognized tax benefits		7	%		0	%		(2	%)		0	%
Taxation on Canadian operations		0	%		0	%		(3	%)		(1	%)
State income taxes		2	%		1	%		1	%		2	%
Other		0	%		(1	%)		3	%		1	%
Effective income tax rate		15	%		30	%		5	%		35	%