Long-Term Debt (Parenthetical) (Detail)	Dec. 31, 2011	Dec. 31, 2010
4.625% Notes due July 15, 2013
Debt Instrument [Line Items]
Notes payable, interest rate	4.625%	4.625%
5.300% Notes due October 15, 2014
Debt Instrument [Line Items]
Notes payable, interest rate	5.30%	5.30%
5.125% Notes due July 1, 2017
Debt Instrument [Line Items]
Notes payable, interest rate	5.125%	5.125%
6.050% Notes due January 15, 2018
Debt Instrument [Line Items]
Notes payable, interest rate	6.05%	6.05%
5.500% Notes due August 15, 2019
Debt Instrument [Line Items]
Notes payable, interest rate	5.50%	5.50%
4.875% Notes due February 1, 2021
Debt Instrument [Line Items]
Notes payable, interest rate	4.875%
6.750% Notes due August 15, 2033
Debt Instrument [Line Items]
Notes payable, interest rate	6.75%	6.75%
Services Company 3.60% ESOP Notes due March 28, 2011
Debt Instrument [Line Items]
Notes payable, interest rate		3.60%