Retirement Benefits Table - Components of Pension Expense (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 0	$ 2
Interest cost	8	9
Expected return on plan assets	(11)	(15)
Net periodic benefit cost subtotal	(5)	(5)
Regulatory adjustment	0	2
Net periodic benefit cost	(5)	(3)
Defined Benefit Plan, Amortization of Gains (Losses)	1	(1)
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Settlements	1	2
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0
Interest cost	1	2
Expected return on plan assets	(2)	(3)
Net periodic benefit cost subtotal	(1)	(1)
Regulatory adjustment	0	0
Net periodic benefit cost	(1)	(1)
Defined Benefit Plan, Amortization of Gains (Losses)	0	0
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Settlements	$ 0	$ 0