Retirement Plans (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Net Periodic Pension And OPEB Cost/(Benefit) [Abstract]
Changes in fair value	5 years
Pension [Member]
Net Periodic Pension And OPEB Cost/(Benefit) [Abstract]
Service cost	$ 24,000,000	$ 18,000,000
Interest cost	40,000,000	39,000,000
Expected return on plan assets	(64,000,000)	(58,000,000)
Amortization of prior service cost
Amortization of actuarial loss	26,000,000	17,000,000
Net periodic pension cost	26,000,000	16,000,000
Cash contributions to qualified pension plan	0
OPEB [Member]
Net Periodic Pension And OPEB Cost/(Benefit) [Abstract]
Service cost	1,000,000	1,000,000
Interest cost	3,000,000	4,000,000
Expected return on plan assets
Amortization of prior service cost	(2,000,000)	(3,000,000)
Amortization of actuarial loss	3,000,000	2,000,000
Net periodic pension cost	$ 5,000,000	$ 4,000,000