Fair Value

3 Months Ended

Mar. 31, 2012

Fair Value Disclosures [Abstract]

Fair Value Disclosures [Text Block]

FAIR VALUE MEASUREMENTS

Fair value is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. Fair value is a market-based measurement that is determined based on assumptions that market participants would use in pricing an asset or liability. A three-tier fair value hierarchy is used to prioritize the inputs in measuring fair value as follows:

• Level 1. Observable inputs such as quoted prices in active markets;

• Level 2. Inputs, other than quoted prices in active markets, that are observable either directly or indirectly; and

• Level 3. Unobservable inputs in which there is little or no market data, which require the reporting entity to develop its own assumptions.

Assets (Liabilities) Measured at Fair Value on a Recurring Basis

(in millions)	March 31, 2012			Level 1		Level 2			Level 3
Cash equivalents	$	2,721		$	2,721	$	—		$	—
Short-term investments	959			959		—			—
Restricted cash equivalents and short-term investments	409			409		—			—
Long-term investments	176			56		26			94
Hedge derivatives, net
Fuel hedge contracts	190			—		190			—
Interest rate contracts	(91		)	—		(91		)	—
Foreign currency exchange contracts	34			—		34			—

(in millions)	December 31, 2011			Level 1		Level 2			Level 3
Cash equivalents	$	2,357		$	2,357	$	—		$	—
Short-term investments	958			958		—			—
Restricted cash equivalents and short-term investments	341			341		—			—
Long-term investments	188			55		24			109
Hedge derivatives, net
Fuel hedge contracts	70			—		70			—
Interest rate contracts	(91		)	—		(91		)	—
Foreign currency exchange contracts	(89		)	—		(89		)	—

Cash Equivalents, Short-term Investments and Restricted Cash Equivalents and Short-term Investments. Cash equivalents and short-term investments generally consist of money market funds and treasury bills. Restricted cash equivalents and short-term investments are primarily held to meet certain projected self-insurance obligations and generally consist of money market funds and time deposits. Cash equivalents, short-term investments and restricted cash equivalents and short-term investmentsare recorded at cost, which approximates fair value. Fair value is based on the market approach using prices and other relevant information generated by market transactions involving identical or comparable assets.

Long-term Investments. Our long-term investments are comprised of commercial investments, auction rate securities and other long-term investments. Any change in the fair value of these securities is recorded in accumulated other comprehensive income (loss) ("AOCI") or earnings, as appropriate. These investments are classified in other noncurrent assets.

Hedge Derivatives. Our derivative contracts are generally privately negotiated with counterparties without going through a public exchange. Accordingly, our fair value assessments give consideration to the risk of counterparty default (as well as our own credit risk).

• Fuel Derivatives. Our fuel hedge portfolio generally consists of call options; put options, combinations of two or more call options and put options; swap contracts; and futures contracts.The products underlying the hedge contracts include heating oil, crude oil, jet fuel and diesel, as these commodities are highly correlated with the price of jet fuel. Option contracts are valued under the income approach using option pricing models based on data either readily observable in public markets, derived from public markets or provided by counterparties who regularly trade in public markets. Volatilities used in these valuations ranged from 13% to 37% depending on the maturity dates, underlying commodities and strike prices of the option contracts. Swap contracts are valued under the income approach using a discounted cash flow model based on data either readily observable or derived from public markets. Discount rates used in these valuations vary with the maturity dates of the respective contracts and are based on LIBOR. Futures contracts are traded on a public exchange and are valued based on quoted market prices.

• Interest Rate Derivatives. Our interest rate derivatives consist of swap contracts and are valued primarily based on data readily observable in public markets.

• Foreign Currency Derivatives. Our foreign currency derivatives consist of Japanese yen and Canadian dollar forward contracts and are valued based on data readily observable in public markets.

For additional information regarding the composition and classification of our derivative contracts, see Note 3.