Variable Interest Entities, Consolidated Balance Sheet (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016	Dec. 31, 2015
Assets
Cash and cash equivalents	$ 791	$ 900	$ 899	$ 985
Accounts receivable	749	753
Other current assets	26	32
Licenses	2,235	1,895
Property, plant and equipment, net	3,373	3,555
Other assets and deferred charges	348	434
Liabilities
Current liabilities	786	887
Consolidated Variable Interest Entities
Assets
Cash and cash equivalents	2	2
Accounts receivable	402	39
Other current assets	6	6
Licenses	649	649
Property, plant and equipment, net	87	93
Other assets and deferred charges	241	15
Total assets	1,387	804
Liabilities
Current liabilities	40	18
Deferred liabilities and credits	12	12
Total liabilities	$ 52	$ 30