Derivatives (Narrative) (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Mar. 31, 2012
Notes Payable And Other Payables [Member] | 3.50% Senior Notes Due In March 2016 [Member]
Derivative [Line Items]
Debt instrument, interest rate (in percentage)		3.50%
Maturity period of senior notes		March 2016
Interest Rate Swap [Member]
Derivative [Line Items]
Notional amount of interest rate swap agreements			$ 500
Hedge agreements	3.50 percent senior notes due in March 2016
Gain on the termination of the transactions		20
Hedge ineffectiveness of interest rate swaps		$ 0