Employee Benefit Plans (Schedule Of Level 3 Reconciliation) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Balance as of January 1	$ 16,284
Balance as of December 31	15,793	$ 16,284
Other Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance as of January 1	2,096
Balance as of December 31	2,040	2,096
Other Benefits [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance as of January 1	387
Balance as of December 31	343	387
Other Benefits [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance as of January 1	1,604
Balance as of December 31	1,555	1,604
Other Benefits [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance as of January 1	105	93
Relating to assets still held at the reporting date	4	6
Relating to assets sold during the period	0	0
Purchases	34	7
Settlements	(1)	(1)
Balance as of December 31	142	105
Pension Plans Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance as of January 1	14,188
Balance as of December 31	13,753	14,188
Pension Plans Defined Benefit [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance as of January 1	3,958
Balance as of December 31	3,572	3,958
Pension Plans Defined Benefit [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance as of January 1	8,340
Balance as of December 31	8,128	8,340
Pension Plans Defined Benefit [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance as of January 1	1,890	1,723
Relating to assets still held at the reporting date	65	101
Relating to assets sold during the period	1	4
Purchases	109	79
Settlements	(12)	(17)
Balance as of December 31	2,053	1,890
Real Estate [Member] | Other Benefits [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance as of January 1	49	38
Relating to assets still held at the reporting date	5	4
Relating to assets sold during the period	0	0
Purchases	23	7
Settlements	0	0
Balance as of December 31	77	49
Real Estate [Member] | Pension Plans Defined Benefit [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance as of January 1	675	544
Relating to assets still held at the reporting date	63	54
Relating to assets sold during the period	0	0
Purchases	17	78
Settlements	(2)	(1)
Balance as of December 31	753	675
Absolute Return [Member] | Other Benefits [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance as of January 1	55	53
Relating to assets still held at the reporting date	(1)	2
Relating to assets sold during the period	0	0
Purchases	11	0
Settlements	0	0
Balance as of December 31	65	55
Absolute Return [Member] | Pension Plans Defined Benefit [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance as of January 1	577	554
Relating to assets still held at the reporting date	(7)	23
Relating to assets sold during the period	0	0
Purchases	90	0
Settlements	0	0
Balance as of December 31	660	577
Corporate Fixed Income Securities [Member] | Other Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance as of January 1	1,219
Balance as of December 31	1,160	1,219
Corporate Fixed Income Securities [Member] | Other Benefits [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance as of January 1	163
Balance as of December 31	150	163
Corporate Fixed Income Securities [Member] | Other Benefits [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance as of January 1	1,055
Balance as of December 31	1,010	1,055
Corporate Fixed Income Securities [Member] | Other Benefits [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance as of January 1	1	2
Relating to assets still held at the reporting date	0	0
Relating to assets sold during the period	0	0
Purchases	0	0
Settlements	(1)	(1)
Balance as of December 31	0	1
Corporate Fixed Income Securities [Member] | Pension Plans Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance as of January 1	8,424
Balance as of December 31	7,997	8,424
Corporate Fixed Income Securities [Member] | Pension Plans Defined Benefit [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance as of January 1	2,068
Balance as of December 31	1,841	2,068
Corporate Fixed Income Securities [Member] | Pension Plans Defined Benefit [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance as of January 1	5,718
Balance as of December 31	5,516	5,718
Corporate Fixed Income Securities [Member] | Pension Plans Defined Benefit [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance as of January 1	638	625
Relating to assets still held at the reporting date	9	24
Relating to assets sold during the period	1	4
Purchases	2	1
Settlements	(10)	(16)
Balance as of December 31	$ 640	$ 638