Employee Benefit Plans (Schedule Of Fair Value Of Plan Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	$ 1,922	$ 2,194
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	875	796
Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	1,047	1,398
Common stock - U.S. companies [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	196	180
Common stock - U.S. companies [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	196	180
Common stock - International companies [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	8	6
Common stock - International companies [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	8	6
Equity mutual funds - Emerging markets [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	58	62
Equity mutual funds - Emerging markets [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	58	62
Equity mutual funds - International [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	105	91
Equity mutual funds - International [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	105	91
Equity mutual funds - Large cap U.S. [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	409	362
Equity mutual funds - Large cap U.S. [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	409	362
Common collective trust funds - International equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	278	370
Common collective trust funds - International equity [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	278	370
Common collective trust funds - Large cap U.S. equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	45	33
Common collective trust funds - Large cap U.S. equity [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	45	33
Common collective trust funds - Fixed income [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	193	500
Common collective trust funds - Fixed income [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	193	500
Common collective trust funds - Other [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	47	35
Common collective trust funds - Other [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	47	35
Debt instruments - Corporate bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	457	422
Debt instruments - Corporate bonds [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	457	422
Debt instruments - U.S. Treasury instruments [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	99	95
Debt instruments - U.S. Treasury instruments [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	99	95
Debt instruments - U.S. government agency, state and local government bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	24	37
Debt instruments - U.S. government agency, state and local government bonds [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	24	37
Other Debt Instruments [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	3	1
Other Debt Instruments [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	$ 3	$ 1