Fair Value Measurements (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Assets
Available-for-sale securities	$ 1,498	$ 1,447
U.S. governmental agency
Assets
Available-for-sale securities	279	310
U.S. treasury bonds
Assets
Available-for-sale securities	12	10
Other U.S. and non-U.S. government bonds
Assets
Available-for-sale securities	123	92
Corporate bonds
Assets
Available-for-sale securities	604	572
Asset-backed securities
Assets
Available-for-sale securities	98	111
Residential mortgage-backed securities
Assets
Available-for-sale securities	29	30
Commercial mortgage-backed securities
Assets
Available-for-sale securities	143	145
Large capitalization value
Assets
Available-for-sale securities	168	148
Smaller company growth
Assets
Available-for-sale securities	42	29
Level 1 \| Recurring basis
Assets
Available-for-sale securities	222	187
Total Assets	222	187
Level 1 \| U.S. treasury bonds \| Recurring basis
Assets
Available-for-sale securities	12	10
Level 1 \| Large capitalization value \| Recurring basis
Assets
Available-for-sale securities	168	148
Level 1 \| Smaller company growth \| Recurring basis
Assets
Available-for-sale securities	42	29
Level 2 \| Recurring basis
Assets
Available-for-sale securities	1,276	1,260
Derivative financial instruments, net	183	145
Total Assets	1,459	1,405
Level 2 \| Other U.S. and non-U.S. government bonds \| Recurring basis
Assets
Available-for-sale securities	123	92
Level 2 \| Corporate bonds \| Recurring basis
Assets
Available-for-sale securities	604	572
Level 2 \| Asset-backed securities \| Recurring basis
Assets
Available-for-sale securities	98	111
Level 2 \| Mortgage-backed debt securities \| U.S. governmental agency \| Recurring basis
Assets
Available-for-sale securities	279	310
Level 2 \| Residential mortgage-backed securities \| Recurring basis
Assets
Available-for-sale securities	29	30
Level 2 \| Commercial mortgage-backed securities \| Recurring basis
Assets
Available-for-sale securities	143	145
Level 3 \| Recurring basis
Liabilities
Guarantees	7	7
Total Liabilities	7	7
Available-for-sale securities \| Recurring basis
Assets
Available-for-sale securities	1,498	1,447
Derivative financial instruments, net	183	145
Total Assets	1,681	1,592
Liabilities
Guarantees	7	7
Total Liabilities	7	7
Available-for-sale securities \| U.S. treasury bonds \| Recurring basis
Assets
Available-for-sale securities	12	10
Available-for-sale securities \| Other U.S. and non-U.S. government bonds \| Recurring basis
Assets
Available-for-sale securities	123	92
Available-for-sale securities \| Corporate bonds \| Recurring basis
Assets
Available-for-sale securities	604	572
Available-for-sale securities \| Asset-backed securities \| Recurring basis
Assets
Available-for-sale securities	98	111
Available-for-sale securities \| Mortgage-backed debt securities \| U.S. governmental agency \| Recurring basis
Assets
Available-for-sale securities	279	310
Available-for-sale securities \| Residential mortgage-backed securities \| Recurring basis
Assets
Available-for-sale securities	29	30
Available-for-sale securities \| Commercial mortgage-backed securities \| Recurring basis
Assets
Available-for-sale securities	143	145
Available-for-sale securities \| Large capitalization value \| Recurring basis
Assets
Available-for-sale securities	168	148
Available-for-sale securities \| Smaller company growth \| Recurring basis
Assets
Available-for-sale securities	$ 42	$ 29

This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents Available-for-sale Securities which consist of all investments in certain debt and equity securities neither classified as trading or held-to-maturity securities. A debt security represents a creditor relationship with an enterprise. Debt securities include, among other items, US Treasury securities, US government securities, municipal securities, corporate bonds, convertible debt, commercial paper, and all securitized debt instruments. An equity security represents an ownership interest in an enterprise or the right to acquire or dispose of an ownership interest in an enterprise at fixed or determinable prices. Equity securities include, among other things, common stock, certain preferred stock, warrant rights, call options, and put options, but do not include convertible debt. An entity may opt to provide the reader with additional narrative text to better understand the nature of investments in debt and equity securities which are categorized as Available-for-sale.

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Fair values as of the balance sheet date of the net amount of all assets and liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments.

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- Definition

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