Long-Term Debt (Parenthetical) (Detail)	Dec. 31, 2013	Dec. 31, 2012
Debt Instrument [Line Items]
Debt maturity date	2018-10
3.125% senior notes due 2015
Debt Instrument [Line Items]
Debt interest rate	3.125%	3.125%
Debt maturity date	2015-10	2015-10
3.125% senior notes due 2016
Debt Instrument [Line Items]
Debt interest rate	3.125%	3.125%
Debt maturity date	2016-06	2016-06
6.8% senior notes due 2017
Debt Instrument [Line Items]
Debt interest rate	6.80%	6.80%
Debt maturity date	2017-11	2017-11
4.625% senior notes due 2020
Debt Instrument [Line Items]
Debt interest rate	4.625%	4.625%
Debt maturity date	2020-10	2020-10
4.75% senior notes due 2021
Debt Instrument [Line Items]
Debt interest rate	4.75%	4.75%
Debt maturity date	2021-06	2021-06
3.5% senior notes due 2022
Debt Instrument [Line Items]
Debt interest rate	3.50%	3.50%
Debt maturity date	2022-10	2022-10