Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Cash and Cash Equivalents:
Total cash and cash equivalents	$ 1,454	$ 1,720
Derivative Asset:
Total derivative asset		111
Short-term investments:
Total short-term investments	157
Long-term investments:
Total long-term investments	93
SKYCIG | Earn out liability
Other liabilities:
Total other liabilities	25
Prime money market funds
Cash and Cash Equivalents:
Total cash and cash equivalents	1,454	1,720
Corporate debt securities
Short-term investments:
Total short-term investments	63
Long-term investments:
Total long-term investments	86
Agency obligations
Short-term investments:
Total short-term investments	59
Long-term investments:
Total long-term investments	7
Commercial paper
Short-term investments:
Total short-term investments	22
International government obligations
Short-term investments:
Total short-term investments	13
Interest rate swaps - fixed to floating rate
Derivative Asset:
Total derivative asset	60	111
Level 1
Cash and Cash Equivalents:
Total cash and cash equivalents	1,454	1,720
Level 1 | Prime money market funds
Cash and Cash Equivalents:
Total cash and cash equivalents	1,454	1,720
Level 2
Derivative Asset:
Total derivative asset		111
Short-term investments:
Total short-term investments	157
Long-term investments:
Total long-term investments	93
Level 2 | Corporate debt securities
Short-term investments:
Total short-term investments	63
Long-term investments:
Total long-term investments	86
Level 2 | Agency obligations
Short-term investments:
Total short-term investments	59
Long-term investments:
Total long-term investments	7
Level 2 | Commercial paper
Short-term investments:
Total short-term investments	22
Level 2 | International government obligations
Short-term investments:
Total short-term investments	13
Level 2 | Interest rate swaps - fixed to floating rate
Derivative Asset:
Total derivative asset	60	111
Level 3 | SKYCIG | Earn out liability
Other liabilities:
Total other liabilities	$ 25