Retirement Plans (Reconciliation Of Benefit Obligations And Plan Or Trust Assets And Resulting Funded Status Of Defined Benefit Retirement Plans) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Pension Benefits
Change in Benefit Obligation
Service cost	$ (186)	$ (298)	$ (266)
Interest cost	(532)	(492)	(523)
Actuarial loss	566
Change in Plan/Trust Assets
Fair value of assets at beginning of year	8,476
Employer contributions	513
Fair value of assets at end of year	9,084	8,476
Other Postretirement Benefit Plans, Defined Benefit
Change in Benefit Obligation
Service cost	(12)	(15)	(12)
Interest cost	(52)	(53)	(59)
Actuarial loss	28
Change in Plan/Trust Assets
Fair value of assets at beginning of year	519
Fair value of assets at end of year	553	519
Change in Benefit Obligation [Member] | Pension Benefits
Change in Benefit Obligation
Benefit obligation at beginning of year	(11,013)	(12,114)
Service cost	(186)	(298)
Interest cost	(532)	(492)
Amendments	(1)	234
Actuarial loss	(2,083)	1,094
Settlement/curtailment/other	64	2
Benefits paid	515	561
Benefit obligation at end of year	(13,236)	(11,013)
Change in Benefit Obligation [Member] | Other Postretirement Benefit Plans, Defined Benefit
Change in Benefit Obligation
Benefit obligation at beginning of year	(1,183)	(1,384)
Service cost	(12)	(15)
Interest cost	(52)	(53)
Amendments	55	0
Actuarial loss	(30)	177
Settlement/curtailment/other	15	11
Benefits paid	77	81
Benefit obligation at end of year	(1,130)	(1,183)
Change in Plan/Trust Assets [Member] | Pension Benefits
Change in Plan/Trust Assets
Fair value of assets at beginning of year	8,476	7,227
Actual return on plan assets	664	1,200
Employer contributions	513	601
Settlement/curtailment/other	(65)	(3)
Benefits paid	(504)	(549)
Fair value of assets at end of year	9,084	8,476
Funded status at end of year	(4,152)	(2,537)
Change in Plan/Trust Assets [Member] | Other Postretirement Benefit Plans, Defined Benefit
Change in Plan/Trust Assets
Fair value of assets at beginning of year	519	426
Actual return on plan assets	68	116
Employer contributions	6	25
Settlement/curtailment/other	(1)	0
Benefits paid	(39)	(48)
Fair value of assets at end of year	553	519
Funded status at end of year	$ (577)	$ (664)