Goodwill (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Oct. 04, 2011
Changes in carrying amount of goodwill
Balance at the beginning of the period	$ 2,565	$ 2,541	$ 1,123
Effect of foreign currency rate change		24
Goodwill adjustments	12
Balance at the end of the period	$ 2,577	$ 2,565	$ 1,123