Intangible Assets (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	$ 1,865		$ 1,865
Finite-Lived intangible assets, accumulated amortization	631		484
Finite-lived intangible assets, net	1,234		1,381
Amortization expense	147	75
Estimated amortization expense
2014	587
2015	373
2016	237
2017	103
2018	81
Directory services agreements
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	666		666
Finite-Lived intangible assets, accumulated amortization	150		97
Finite-lived intangible assets, net	516		569
Client relationships
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	924		924
Finite-Lived intangible assets, accumulated amortization	423		348
Finite-lived intangible assets, net	501		576
Trademarks and domain names
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	222		222
Finite-Lived intangible assets, accumulated amortization	44		29
Finite-lived intangible assets, net	178		193
Patented technologies
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	42		42
Finite-Lived intangible assets, accumulated amortization	7		4
Finite-lived intangible assets, net	35		38
Advertising commitment
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	11		11
Finite-Lived intangible assets, accumulated amortization	7		6
Finite-lived intangible assets, net	$ 4		$ 5