Employee Benefit Plans (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Employee Benefit Plans (Textual)
Gain arising during the period related to plan amendments			$ 0	$ 328
Pension Plan [Member]
Components of net periodic benefit cost:
Service cost	30	34	90	105
Interest cost	23	21	69	65
Expected return on plan assets	(34)	(33)	(100)	(99)
Amortization of:
Prior service credit	(6)	(5)	(16)	(14)
Net actuarial (gain) loss	9	14	26	43
Net periodic benefit cost	22	31	69	100
Employee Benefit Plans (Textual)
Decrease to pension liabilities related to plan amendments				328
Gain arising during the period related to plan amendments				328
Contributions to benefit plans			31	29
Other Postretirement Benefit Plan [Member]
Components of net periodic benefit cost:
Service cost	3	3	6	9
Interest cost	4	4	12	13
Expected return on plan assets	0	0	0	0
Amortization of:
Prior service credit	(5)	(4)	(14)	(10)
Net actuarial (gain) loss	(1)	0	(1)	0
Net periodic benefit cost	1	3	3	12
Employee Benefit Plans (Textual)
Contributions to benefit plans			$ 14	$ 13