Derivative Instruments and Hedging Activities - Additional Information (Detail) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended			12 Months Ended
	Mar. 31, 2014 Forward Starting Interest Rate Swap [Member] Cash Flow Hedging [Member] USD ($)	Dec. 31, 2013 Forward Starting Interest Rate Swap [Member] Cash Flow Hedging [Member]	Dec. 31, 2009 Forward Starting Interest Rate Swap [Member] Cash Flow Hedging [Member] USD ($)	Dec. 31, 2013 Forward Starting Interest Rate Swap [Member] Cash Flow Hedging [Member] Current accrued liabilities [Member] USD ($)	Dec. 31, 2014 Interest Rate Swaps [Member] Fair Value Hedge [Member] USD ($)	Dec. 31, 2013 Interest Rate Swaps [Member] Fair Value Hedge [Member] USD ($)	Dec. 31, 2014 Foreign Currency Derivatives [Member] October 31, 2016 [Member] Principal [Member] CAD	Dec. 31, 2013 Foreign Currency Derivatives [Member] October 31, 2016 [Member] Principal [Member] CAD	Dec. 31, 2014 Foreign Currency Derivatives [Member] Cash Flow Hedging [Member] October 31, 2016 [Member] CAD	Dec. 31, 2014 Foreign Currency Derivatives [Member] Cash Flow Hedging [Member] October 31, 2017 [Member] CAD	Dec. 31, 2014 Foreign Currency Derivatives [Member] Cash Flow Hedging [Member] October 31, 2018 [Member] CAD	Dec. 31, 2014 Treasury rate locks [Member] Cash Flow Hedging [Member] USD ($)	Dec. 31, 2013 Treasury rate locks [Member] Cash Flow Hedging [Member] USD ($)
Derivative Instruments, Gain (Loss) [Line Items]
Increase in carrying value of debt instruments from fair value hedge accounting for interest rate swaps					$ 45	$ 59
Notional amount of derivatives	175		525
Maximum term of cash flow hedges		10 years
Fair value of forward-starting swaps (interest rate derivatives)				28
Cash received (paid) to settle hedges	36
Deferred losses, net of taxes, related to cash flow hedges included in accumulated other comprehensive income												50	34
Deferred losses scheduled to be reclassified out of accumulated other comprehensive into interest expense over next 12 months, pre-tax												11
Notional amount of derivatives							370	370	70	150	150