Financing Arrangements and Debt - Additional Information (Detail) (USD $)	6 Months Ended
	Jun. 30, 2013
Debt Disclosure [Abstract]
Credit facility maximum borrowing capacity	$ 2,000,000,000
Credit facility, maturity date	Jun. 30, 2017
Credit facility interest rate above LIBOR	1.25%
Line of credit facility fee	0.25%
Capital lease term	25 years
Capital lease expiration period	15 years
Capital lease expiration date	Jun. 30, 2028
Lease obligation	$ 356,170,000