Certain Employee Benefit and Stock Based Compensation Plans (Net Periodic Pension and Postretirement Benefits Costs) (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
Qualified Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 26	$ 29	$ 51	$ 57
Interest cost	47	43	94	85
Expected return on plan assets	(72)	(72)	(144)	(144)
Amortization of prior service credit	(2)	(2)	(4)	(4)
Amortization of actuarial losses		21		43
Net periodic cost/(benefit)	(1)	19	(3)	37
Nonqualified Retirement Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	1	2	2
Interest cost	3	3	6	6
Amortization of actuarial losses	1	2	2	4
Net periodic cost/(benefit)	5	6	10	12
Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	2	2	3
Interest cost	4	4	8	8
Amortization of prior service credit		(1)		(2)
Net periodic cost/(benefit)	$ 5	$ 5	$ 10	$ 9