Incentive Plans (Summary Of Activity Of Executive Continuity And Restricted Stock Award Program) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares/units, outstanding	7,275,934	8,117,489	8,660,855
Shares/units, granted	1,863,623	3,682,663	3,148,445
Shares/units, shares issued	(2,959,160)	(4,025,111)	(3,262,760)
Shares/units, forfeited	(322,664)	(499,107)	(429,051)
Shares/Units, outstanding	5,857,733	7,275,934	8,117,489
Weighted average grant date fair value, outstanding	$ 34.98	$ 31.20	$ 28.37
Weighted average grant date fair value, granted	53.25	46.82	40.76
Weighted average grant date fair value, shares issued	37.09	37.18	32.48
Weighted average grant date fair value, outstanding	38.69	34.98	31.20
Weighted average grant date fair value, forfeited	$ 53.97	$ 43.10	$ 34.58
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares/units, outstanding	114,599	112,374	151,549
Shares/units, granted	36,300	89,500	67,100
Shares/units, shares issued	(27,365)	(83,275)	(88,775)
Shares/units, forfeited	(3,166)	(4,000)	(17,500)
Shares/Units, outstanding	120,368	114,599	112,374
Weighted average grant date fair value, outstanding	$ 47.03	$ 36.24	$ 30.49
Weighted average grant date fair value, granted	50.06	48.19	44.41
Weighted average grant date fair value, shares issued	45.35	33.78	32.30
Weighted average grant date fair value, outstanding	48.24	47.03	36.24
Weighted average grant date fair value, forfeited	$ 50.04	$ 45.88	$ 37.75