Fair Value Measurements - Financial Assets and Liabilities Measured on Recurring Basis (Detail) (Fair Value, Measurements, Recurring, USD $) In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Assets:
Asset	$ 54	$ 37
Liabilities:
Liabilities	36	44
Investments in equity securities
Assets:
Asset	28	13
Plan Assets For Deferred Compensation
Assets:
Asset	23	22
Investment In Mutual Funds
Assets:
Asset	2	2
Interest Rate Swap
Liabilities:
Liabilities	13	22
Deferred Compensation Liabilities
Liabilities:
Liabilities	23	22
Level 1
Assets:
Asset	54	37
Liabilities:
Liabilities	23	22
Level 1 | Investments in equity securities
Assets:
Asset	28	13
Level 1 | Plan Assets For Deferred Compensation
Assets:
Asset	23	22
Level 1 | Investment In Mutual Funds
Assets:
Asset	2	2
Level 1 | Interest Rate Swap
Liabilities:
Liabilities
Level 1 | Deferred Compensation Liabilities
Liabilities:
Liabilities	23	22
Level 2
Assets:
Asset
Liabilities:
Liabilities	13	22
Level 2 | Investments in equity securities
Assets:
Asset
Level 2 | Plan Assets For Deferred Compensation
Assets:
Asset
Level 2 | Investment In Mutual Funds
Assets:
Asset
Level 2 | Interest Rate Swap
Liabilities:
Liabilities	13	22
Level 2 | Deferred Compensation Liabilities
Liabilities:
Liabilities
Level 3
Assets:
Asset
Liabilities:
Liabilities
Level 3 | Investments in equity securities
Assets:
Asset
Level 3 | Plan Assets For Deferred Compensation
Assets:
Asset
Level 3 | Investment In Mutual Funds
Assets:
Asset
Level 3 | Interest Rate Swap
Liabilities:
Liabilities
Level 3 | Deferred Compensation Liabilities
Liabilities:
Liabilities