Fair Value Measurements (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Assets
Available-for-sale securities	$ 1,561	$ 1,447
Fair Value, Measurements, Recurring
Assets
Available-for-sale securities	1,561	1,447
Derivative financial instruments, net	156	145
Total Assets	1,717	1,592
Liabilities
Guarantees	17	7
Total Liabilities	17	7
U.S. treasury bonds
Assets
Available-for-sale securities	10	10
U.S. treasury bonds \| Fair Value, Measurements, Recurring
Assets
Available-for-sale securities	10	10
Other U.S. and non-U.S. government bonds
Assets
Available-for-sale securities	118	92
Other U.S. and non-U.S. government bonds \| Fair Value, Measurements, Recurring
Assets
Available-for-sale securities	118	92
Corporate bonds
Assets
Available-for-sale securities	672	572
Corporate bonds \| Fair Value, Measurements, Recurring
Assets
Available-for-sale securities	672	572
Asset-backed Securities
Assets
Available-for-sale securities	94	111
Asset-backed Securities \| Fair Value, Measurements, Recurring
Assets
Available-for-sale securities	94	111
U.S. governmental agency \| Fair Value, Measurements, Recurring
Assets
Available-for-sale securities	298	310
Residential
Assets
Available-for-sale securities	27	30
Residential \| Fair Value, Measurements, Recurring
Assets
Available-for-sale securities	27	30
Commercial
Assets
Available-for-sale securities	131	145
Commercial \| Fair Value, Measurements, Recurring
Assets
Available-for-sale securities	131	145
Large capitalization value
Assets
Available-for-sale securities	177	148
Large capitalization value \| Fair Value, Measurements, Recurring
Assets
Available-for-sale securities	177	148
Smaller company growth
Assets
Available-for-sale securities	34	29
Smaller company growth \| Fair Value, Measurements, Recurring
Assets
Available-for-sale securities	34	29
Level 1 \| Fair Value, Measurements, Recurring
Assets
Available-for-sale securities	221	187
Derivative financial instruments, net	0	0
Total Assets	221	187
Liabilities
Guarantees	0	0
Total Liabilities	0	0
Level 1 \| U.S. treasury bonds \| Fair Value, Measurements, Recurring
Assets
Available-for-sale securities	10	10
Level 1 \| Other U.S. and non-U.S. government bonds \| Fair Value, Measurements, Recurring
Assets
Available-for-sale securities	0	0
Level 1 \| Corporate bonds \| Fair Value, Measurements, Recurring
Assets
Available-for-sale securities	0	0
Level 1 \| Asset-backed Securities \| Fair Value, Measurements, Recurring
Assets
Available-for-sale securities	0	0
Level 1 \| U.S. governmental agency \| Fair Value, Measurements, Recurring
Assets
Available-for-sale securities	0	0
Level 1 \| Residential \| Fair Value, Measurements, Recurring
Assets
Available-for-sale securities	0	0
Level 1 \| Commercial \| Fair Value, Measurements, Recurring
Assets
Available-for-sale securities	0	0
Level 1 \| Large capitalization value \| Fair Value, Measurements, Recurring
Assets
Available-for-sale securities	177	148
Level 1 \| Smaller company growth \| Fair Value, Measurements, Recurring
Assets
Available-for-sale securities	34	29
Level 2 \| Fair Value, Measurements, Recurring
Assets
Available-for-sale securities	1,340	1,260
Derivative financial instruments, net	156	145
Total Assets	1,496	1,405
Liabilities
Guarantees	0	0
Total Liabilities	0	0
Level 2 \| U.S. treasury bonds \| Fair Value, Measurements, Recurring
Assets
Available-for-sale securities	0	0
Level 2 \| Other U.S. and non-U.S. government bonds \| Fair Value, Measurements, Recurring
Assets
Available-for-sale securities	118	92
Level 2 \| Corporate bonds \| Fair Value, Measurements, Recurring
Assets
Available-for-sale securities	672	572
Level 2 \| Asset-backed Securities \| Fair Value, Measurements, Recurring
Assets
Available-for-sale securities	94	111
Level 2 \| U.S. governmental agency \| Fair Value, Measurements, Recurring
Assets
Available-for-sale securities	298	310
Level 2 \| Residential \| Fair Value, Measurements, Recurring
Assets
Available-for-sale securities	27	30
Level 2 \| Commercial \| Fair Value, Measurements, Recurring
Assets
Available-for-sale securities	131	145
Level 2 \| Large capitalization value \| Fair Value, Measurements, Recurring
Assets
Available-for-sale securities	0	0
Level 2 \| Smaller company growth \| Fair Value, Measurements, Recurring
Assets
Available-for-sale securities	0	0
Level 3 \| Fair Value, Measurements, Recurring
Assets
Available-for-sale securities	0	0
Derivative financial instruments, net	0	0
Total Assets	0	0
Liabilities
Guarantees	17	7
Total Liabilities	17	7
Level 3 \| U.S. treasury bonds \| Fair Value, Measurements, Recurring
Assets
Available-for-sale securities	0	0
Level 3 \| Other U.S. and non-U.S. government bonds \| Fair Value, Measurements, Recurring
Assets
Available-for-sale securities	0	0
Level 3 \| Corporate bonds \| Fair Value, Measurements, Recurring
Assets
Available-for-sale securities	0	0
Level 3 \| Asset-backed Securities \| Fair Value, Measurements, Recurring
Assets
Available-for-sale securities	0	0
Level 3 \| U.S. governmental agency \| Fair Value, Measurements, Recurring
Assets
Available-for-sale securities	0	0
Level 3 \| Residential \| Fair Value, Measurements, Recurring
Assets
Available-for-sale securities	0	0
Level 3 \| Commercial \| Fair Value, Measurements, Recurring
Assets
Available-for-sale securities	0	0
Level 3 \| Large capitalization value \| Fair Value, Measurements, Recurring
Assets
Available-for-sale securities	0	0
Level 3 \| Smaller company growth \| Fair Value, Measurements, Recurring
Assets
Available-for-sale securities	$ 0	$ 0

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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