Stock-Based Compensation (Summary Of Nonvested Shares) (Details) - Performance Share Units - $ / shares		12 Months Ended
		Dec. 31, 2016		Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Share Units, Nonvested at beginning of year		1,024,870
Share Units, Granted	[1]	588,615
Share Units, Unearned or forfeited		(15,949)
Share Units, Earned and vested	[2]	(537,897)
Share Units, Nonvested at end of year		1,059,639		1,024,870
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Weighted-average Fair Value per Unit, Nonvested at beginning of year		$ 46.08
Weighted-averageFair Value per Unit, granted		44.13	[1]	$ 52.88	$ 38.90
Weighted-average Fair Value per Unit, Unearned or forfeited		45.07
Weighted-average Fair Value per Unit, Earned and vested	[2]	40.12
Weighted-average Fair Value per Unit, Nonvested at end of year		$ 48.04		$ 46.08

[1] Includes performance share units (share units) granted to certain executive and nonexecutive officers and other eligible employees in 2016 under the 2014 Incentive Plan.

[2] Includes share units granted in 2014 that vested as of December 31, 2016 and were earned pursuant to the terms of the award grants. Also includes share units that vested due to attainment of retirement eligibility by certain employees. Actual shares issued for retirement-eligible employees will vary depending on actual performance over the three-year measurement period.