Per Share Information (Reconciliation of the Numerators and Denominators of the Basic and Diluted Per Share Computations) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended				6 Months Ended
		Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Per Share Information
Net income (loss)		$ 246			$ 180	$ 456	$ 294
Dividends on preferred stock	[1]	(28)			(28)	(57)	(57)
Net income (loss) attributable to CCIC common stockholders for basic and diluted computations		$ 218			$ 152	$ 399	$ 237
Basic weighted-average number of common stock outstanding		416			415	415	412
Effect of assumed dilution from potential issuance of common shares relating to restricted stock units		2			1	2	1
Diluted weighted-average number of common shares outstanding		418			416	417	413
Basic		$ 0.52			$ 0.37	$ 0.96	$ 0.58
Diluted		0.52			0.36	0.95	0.57
Dividends/distributions declared per share of common stock (in dollars per share)		1.125			1.05	2.250	2.10
Dividends declared per share of preferred stock		$ 17.1875	$ 17.1875	$ 17.1875	$ 17.1875	$ 34.3750	$ 34.3750

[1] See note 7 for information regarding common and preferred stock dividends declared per share.