Employee Postretirement Benefits (Benefit Cost Information For Defined Benefit Plans And Other Postretirement Benefit Plans) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans
Service cost	$ 10	$ 11
Interest cost	64	68
Expected return on plan assets	(75)	(82)
Recognized net actuarial loss	29	24
Settlements	9	0
Other	(5)	5
Net periodic benefit cost	32	26
Other Postretirement Benefit Plans [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans
Service cost	4	4
Interest cost	8	9
Expected return on plan assets	0	0
Recognized net actuarial loss	0	0
Settlements	0	0
Other	0	0
Net periodic benefit cost	$ 12	$ 13