Fair Value Measurements (Fair Value of Note Payable and Long-Term Debt) (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of note payable	$ 104	$ 104
Total	991	1,045
Senior Debentures 6.900 Percent Due 2028 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Interest rate	6.90%
Debt instrument, year of maturity	2028
Fair value of senior debt	30	31
Senior Debentures 6.920 Percent Due 2028 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Interest rate	6.92%
Debt instrument, year of maturity	2028
Fair value of senior debt	458	479
Senior Notes 6.125 Percent Due 2034 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Interest rate	6.125%
Debt instrument, year of maturity	2034
Fair value of senior debt	399	431
Fair Value, Inputs, Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of note payable	104	104
Total	991	1,045
Fair Value, Inputs, Level 2 [Member] | Senior Debentures 6.900 Percent Due 2028 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of senior debt	30	31
Fair Value, Inputs, Level 2 [Member] | Senior Debentures 6.920 Percent Due 2028 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of senior debt	458	479
Fair Value, Inputs, Level 2 [Member] | Senior Notes 6.125 Percent Due 2034 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of senior debt	$ 399	$ 431