Employee Benefit Plans (Tables)

6 Months Ended

Jun. 30, 2014

Compensation and Retirement Disclosure [Abstract]

Schedule of Net Benefit Costs [Table Text Block]

Net periodic benefit cost (credit) is as follows:

	Pension Benefits
	Three months ended   June 30,						Six months ended    June 30,
	2014			2013			2014			2013
	(Millions)
Components of net periodic benefit cost:
Service cost	$	10		$	11		$	20		$	22
Interest cost	15			13			31			26
Expected return on plan assets	(19		)	(15		)	(38		)	(30		)
Amortization of net actuarial loss	10			15			19			30
Net periodic benefit cost	$	16		$	24		$	32		$	48

	Other Postretirement Benefits
	Three months ended   June 30,						Six months ended    June 30,
	2014			2013			2014			2013
	(Millions)
Components of net periodic benefit cost (credit):
Service cost	$	—		$	—		$	1		$	1
Interest cost	3			3			5			6
Expected return on plan assets	(3		)	(2		)	(6		)	(4		)
Amortization of prior service credit	(5		)	(2		)	(10		)	(4		)
Amortization of net actuarial loss	—			1			—			3
Reclassification to regulatory liability	1			—			2			—
Net periodic benefit cost (credit)	$	(4	)	$	—		$	(8	)	$	2

Schedule of Regulatory Assets / Liabilities [Table Text Block]

Amounts recognized in regulatory assets/liabilities include:

	Three months ended   June 30,						Six months ended    June 30,
	2014			2013			2014			2013
	(Millions)
Amortization of prior service credit	$	(3	)	$	(2	)	$	(6	)	$	(3	)
Amortization of net actuarial loss	—			1			—			2