Segment Information (Details 2) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($) category	Sep. 30, 2016 USD ($)
Operating revenues by products and services
Number of categories of products and services (categories) | category			4
Revenues	$ 4,034	$ 4,382	$ 12,333	$ 13,181
Surcharge amount on customers' bills	129	144	392	435
Strategic services
Operating revenues by products and services
Revenues	1,892	2,027	5,820	6,070
IT and managed services
Operating revenues by products and services
Revenues	$ 169	160	$ 483	483
Facilities-based video services
Operating revenues by products and services
Number of markets	16		16
Legacy services
Operating revenues by products and services
Revenues	$ 1,705	1,888	$ 5,235	5,790
Data integration
Operating revenues by products and services
Revenues	134	163	385	402
IT and managed services data integration
Operating revenues by products and services
Revenues	4	2	14	3
Other revenues
Operating revenues by products and services
Revenues	303	304	893	919
High cost support revenue
Operating revenues by products and services
Revenues	165	171	501	518
Other revenue
Operating revenues by products and services
Revenues	138	133	392	401
Enterprise
Operating revenues by products and services
Revenues	2,171	2,444	6,742	7,321
Enterprise | Enterprise high-bandwidth data services
Operating revenues by products and services
Revenues	767	744	2,296	2,235
Enterprise | Other enterprise strategic services
Operating revenues by products and services
Revenues	182	334	735	989
Enterprise | Voice services
Operating revenues by products and services
Revenues	551	601	1,682	1,834
Enterprise | Enterprise low-bandwidth data services
Operating revenues by products and services
Revenues	289	339	905	1,056
Enterprise | Other enterprise legacy services
Operating revenues by products and services
Revenues	252	265	754	809
Enterprise | Data integration
Operating revenues by products and services
Revenues	130	161	370	398
Consumer
Operating revenues by products and services
Revenues	1,387	1,472	4,201	4,455
Consumer | Consumer broadband services
Operating revenues by products and services
Revenues	673	674	1,995	2,023
Consumer | Other consumer strategic services
Operating revenues by products and services
Revenues	101	115	311	340
Consumer | Voice services
Operating revenues by products and services
Revenues	541	605	1,678	1,854
Consumer | Other consumer legacy services
Operating revenues by products and services
Revenues	72	78	216	237
Consumer | Data integration
Operating revenues by products and services
Revenues	$ 0	0	$ 1	1
Other enterprise strategic services | Restatement adjustment | Enterprise | Strategic services
Operating revenues by products and services
Revenues		12		36
Other enterprise legacy services | Restatement adjustment | Enterprise | Legacy services
Operating revenues by products and services
Revenues		$ (12)		$ (36)