Long-Term Incentive Employee Compensation Rollforward of Outstanding Stock Options (Detail) - $ / shares shares in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Shares
Beginning Balance, Shares	1.9	2.7	4.3
Stock Options Granted, Shares	0.2	0.2	0.4
Stock Options Exercised, Shares	(0.3)	(0.8)	(1.9)
Stock Options Canceled or Expired, Shares	(0.1)	(0.2)	(0.1)
Stock Options Outstanding at the end of Year, Shares	1.7	1.9	2.7
Stock Options Exercisable at the end of year, Shares	1.1	1.1	1.5
Weighted Average Exercise Price
Beginning Balance, Weighted Average Exercise Price	$ 24.20	$ 20.46	$ 18.46
Stock Options Granted, Weighted Average Exercise Price	41.52	43.52	26.82
Stock Options Exercised, Weighted Average Exercise Price	19.87	17.67	17.37
Stock Options Canceled or Expired, Weighted Average Exercise Price	35.95	24.46	16.15
Outstanding, Weighted Average Exercise Price	27.10	24.20	20.46
Stock Options Exercisable at the end of year, Weighted Average Exercise Price	$ 21.75	$ 20.26	$ 18.34