Employee Benefit Plans (Tables)

3 Months Ended

Mar. 31, 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    March 31,
	2014			2013
	(Millions)
Components of net periodic benefit cost:
Service cost	$	10		$	11
Interest cost	16			13
Expected return on plan assets	(19		)	(15		)
Amortization of net actuarial loss	9			15
Net periodic benefit cost	$	16		$	24

	Other Postretirement Benefits
	Three months ended    March 31,
	2014			2013
	(Millions)
Components of net periodic benefit cost (credit):
Service cost	$	1		$	1
Interest cost	2			3
Expected return on plan assets	(3		)	(2		)
Amortization of prior service credit	(5		)	(2		)
Amortization of net actuarial loss	—			2
Reclassification to regulatory liability	1			—
Net periodic benefit cost (credit)	$	(4	)	$	2

Schedule of Regulatory Assets / Liabilities [Table Text Block]

Amounts recognized in regulatory assets/liabilities include:

	Three months ended    March 31,
	2014			2013
	(Millions)
Amortization of prior service credit	$	(3	)	$	(1	)
Amortization of net actuarial loss	—			1