Employee Benefits - Narrative (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended					12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 Pension and Other Retirement Benefit Plans	Sep. 30, 2014 Minimum	Sep. 30, 2014 Maximum	Dec. 31, 2014 Scenario, Forecast Minimum	Dec. 31, 2014 Scenario, Forecast Maximum
Defined Benefit Plan Disclosure [Line Items]
Reduction in pension obligation				$ 395	$ 415
Pension expected contributions- current year			39	295	310
Pension and Other Post Retirement Non-cash Settlement Expense						105	115
Pension and Other Postretirement Benefit Contributions	33.8	20.5
Pension and postretirement expected contributions for next year	$ 25