Capital Stock (Summary Of Stock Option Activity) (Details) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2015 USD ($) $ / shares shares
Number of Shares
Outstanding at beginning of period, Number of Shares | shares	7.3
Granted, Number of Shares | shares	1.3
Exercised, Number of Shares | shares	(2.4)
Forfeited or expired, Number of Shares | shares	(0.2)
Outstanding at end of period, Number of Shares | shares	6.0
Exercisable at end of period, Number of Shares | shares	3.9
Weighted-Average Option Price per Share
Outstanding at beginning of period, Weighted-Average Option Price per Share | $ / shares	$ 70.30
Granted, Weighted-Average Option Price per Share | $ / shares	146.73
Exercised, Weighted-Average Option Price per Share | $ / shares	67.74
Forfeited or expired, Weighted-Average Option Price per Share | $ / shares	102.14
Outstanding at end of period, Weighted-Average Option Price per Share | $ / shares	87.23
Exercisable at end of period, Weighted-Average Option Price per Share | $ / shares	$ 71.96
Outstanding at end of period, Weighted-Average Remaining Contractual Life	4 years 2 months 14 days
Exercisable at end of period, Weighted-Average Remaining Contractual Life	2 years 9 months 2 days
Outstanding at end of period, Aggregate Intrinsic Value | $	$ 322.7
Exercisable at end of period, Aggregate Intrinsic Value | $	$ 263.3