Summary of Significant Accounting Policies (Components of Fixed Assets) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 2,391	$ 2,273
Less-accumulated depreciation and amortization	(1,582)	(1,469)
Property, Plant and Equipment, Net	809	804	822
Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	1,168	1,101
Land and Building [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	412	405
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 811	$ 767

The cumulative amount of depreciation, depletion and amortization (related to property, plant and equipment, but not including land) that has been recognized in the income statement.

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Gross amount of long-lived physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

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- Definition

Amount, net of accumulated depreciation, depletion and amortization, of long-lived physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

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