Acquisitions and Divestitures - Schedule of Acquired Assets and Liabilities Assumed (Detail) - USD ($) $ in Millions			1 Months Ended		13 Months Ended
	Jun. 30, 2018	Jun. 13, 2017	Feb. 28, 2017	Jul. 31, 2016	Jun. 30, 2018	Dec. 31, 2017
Assets acquired:
Goodwill	$ 29,200				$ 29,200	$ 29,172
Yahoo! Inc.
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Cash payment to Yahoo’s equity holders	4,673	$ 4,723
Estimated liabilities to be paid	38	38
Total consideration	4,711	4,761	$ 4,480	$ 4,830
Assets acquired:
Goodwill	2,144	874			2,144
Intangible assets subject to amortization	1,874	2,586			1,874
Property, plant, and equipment	1,799	1,796			1,799
Other	1,460	1,362			1,460
Total assets acquired	7,277	6,618			7,277
Liabilities assumed:
Total liabilities assumed	2,516	1,824			2,516
Net assets acquired:	4,761	4,794			4,761
Noncontrolling interest	(50)	(33)			(50)
Total consideration	$ 4,711	$ 4,761			4,711
Measurement-period adjustments
Cash payment to Yahoo’s equity holders, adjustments					(50)
Estimated liabilities to be paid, adjustments					0
Total consideration, adjustments					(50)
Goodwill, adjustments					1,270
Intangible assets subject to amortization, adjustments					(712)
Property, plant, and equipment, adjustments					3
Other, adjustments					98
Total assets acquired, adjustments					659
Total liabilities assumed, adjustments					692
Net assets acquired, adjustments					(33)
Noncontrolling interest, adjustments					$ (17)