Retirement Plans (Schedule Of Changes In Projected Benefit Obligation And Plan Assets) (Details) - USD ($) $ in Millions		12 Months Ended
	Jun. 30, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Projected Benefit Obligation [Abstract]
OPEB Plan amendment (Note 6)	$ (92)	$ (92)
Pension [Member]
Projected Benefit Obligation [Abstract]
Projected benefit obligation at beginning of year		4,181	$ 4,529
Service cost		80	105	$ 90
Interest cost		160	145	142
Actuarial loss/(gain)		656	(371)
Gross benefits paid		(230)	(227)
Projected benefit obligation at end of year		4,847	4,181	4,529
Plan Assets [Abstract]
Fair value of plan assets at beginning of year		3,887	4,224
Actual return/(loss) on plan assets		841	(139)
Non-qualified plan benefit contributions		30	29
Gross benefits paid		(230)	(227)
Fair value of plan assets at end of year		4,528	3,887	4,224
Defined Benefit Plan, Funded Status of Plan [Abstract]
Funded status at end of year		(319)	(294)
OPEB [Member]
Projected Benefit Obligation [Abstract]
Projected benefit obligation at beginning of year		298	330
Service cost		1	2	2
Interest cost		9	10	10
OPEB Plan amendment (Note 6)		(92)
Actuarial loss/(gain)		11	(20)
Gross benefits paid		(22)	(24)
Projected benefit obligation at end of year		205	298	330
Plan Assets [Abstract]
Fair value of plan assets at beginning of year
Actual return/(loss) on plan assets
Non-qualified plan benefit contributions - OPEB		22	24
Gross benefits paid		(22)	(24)
Fair value of plan assets at end of year
Defined Benefit Plan, Funded Status of Plan [Abstract]
Funded status at end of year		$ (205)	$ (298)