Sale of Data Centers and Colocation Business - Effects of Failed-sale-Leaseback (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Sale Leaseback Transaction [Line Items]
Operating revenue	$ 5,778	$ 5,818	$ 5,902	$ 5,945	$ 5,323	$ 4,034	$ 4,090	$ 4,209	$ 23,443	$ 17,656	$ 17,470
Decrease in cost of sales									(10,862)	(8,203)	(7,774)
Increase in loss on sale of business included in selling, general and administrative expense									(4,165)	(3,508)	(3,447)
Increase in depreciation expense (ongoing)									(5,120)	(3,936)	(3,916)
Increase in interest expense									(2,177)	(1,481)	(1,318)
Decrease in income tax expense									(170)	849	(394)
NET (LOSS) INCOME	$ (2,412)	$ 272	$ 292	$ 115	$ 1,117	$ 92	17	$ 163	(1,733)	1,389	$ 626
Cyxtera Technologies
Sale Leaseback Transaction [Line Items]
Operating revenue									74	49
Decrease in cost of sales									22	15
Increase in loss on sale of business included in selling, general and administrative expense									0	(102)
Increase in depreciation expense (one-time)							$ (44)		0	(44)
Increase in depreciation expense (ongoing)									(69)	(47)
Increase in interest expense									(55)	(39)
Decrease in income tax expense									7	65
NET (LOSS) INCOME									$ (21)	$ (103)