Employee Benefit Plans Employee Benefit Plans (Net Periodic Defined Benefit Cost) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Defined Benefit Plan Disclosure [Line Items]
Net periodic defined benefit cost			$ 19	$ 44
Defined Benefit Pension Plans | Qualified Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	8	10	15	19
Interest cost	22	20	44	39
Expected return on plan assets	(33)	(33)	(66)	(66)
Amortization of prior service cost (credit)	2	1	3	2
Amortization of net loss	7	19	15	38
Net periodic defined benefit cost	6	17	11	32
Defined Benefit Pension Plans | Non-Qualified Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	1	2	2
Interest cost	3	2	5	5
Amortization of prior service cost (credit)	(1)	(1)	(2)	(1)
Amortization of net loss	1	3	3	5
Net periodic defined benefit cost	4	5	8	11
Postretirement Benefit Plan
Defined Benefit Plan Disclosure [Line Items]
Interest cost	1	1	2	2
Expected return on plan assets	(1)	(1)	(2)	(2)
Amortization of net loss	0	1	0	1
Net periodic defined benefit cost	$ 0	$ 1	$ 0	$ 1