Retirement Plans (Schedule Of Net Periodic Benefit Cost And Other Comprehensive Loss (Earnings) For Pension And Other Postretirement Benefit Plans) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Pension Benefits [Member]
Net periodic benefit cost:
Service cost		$ 15	$ 15	$ 33
Interest cost		42	42	52
Expected return on plan assets		(54)	(55)	(58)
Recognition of net actuarial loss (gain)	[1]	19	25	20
Recognition of prior service cost	[1]	2	3	4
Total net periodic benefit cost	[2]	24	30	51
Other comprehensive loss (earnings):
Actuarial loss (gain) arising in current year		(9)	26	5
Prior service cost (credit) arising in current year			2
Recognition of net actuarial loss, including settlement expense, in net periodic benefit cost	[3]	(19)	(43)	(20)
Recognition of prior service cost, including curtailment, in net periodic benefit cost	[3]	(2)	(9)	(4)
Total other comprehensive loss (earnings)		(30)	(24)	(19)
Total recognized		(6)	6	32
Postretirement Benefits [Member]
Net periodic benefit cost:
Service cost				1
Interest cost			1	1
Recognition of net actuarial loss (gain)	[1]	(1)	(1)	(1)
Recognition of prior service cost	[1]	(1)	(1)	(2)
Total net periodic benefit cost	[2]	(2)	(1)	(1)
Other comprehensive loss (earnings):
Actuarial loss (gain) arising in current year		(1)		(1)
Prior service cost (credit) arising in current year				1
Recognition of net actuarial loss, including settlement expense, in net periodic benefit cost	[3]	1	1	1
Recognition of prior service cost, including curtailment, in net periodic benefit cost	[3]	1	1	1
Total other comprehensive loss (earnings)		1	2	2
Total recognized		$ (1)	$ 1	$ 1

[1] These net periodic benefit costs were reclassified out of other comprehensive earnings in the current period.

[2] Net periodic benefit cost is a component of G&A on the accompanying consolidated comprehensive statements of earnings.

[3] These amounts include restructuring costs that were reclassified out of other comprehensive earnings in 2016. See Note 7 for further discussion.