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		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Per Share Information
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	$ 164	$ 115	$ 458	$ 346
Dividends on preferred stock	28	30	85	30
Net income (loss) attributable to CCIC common stockholders for basic and diluted computations	$ 136	$ 85	$ 373	$ 316
Basic weighted-average number of common stock outstanding	415	395	413	374
Effect of assumed dilution from potential issuance of common shares relating to restricted stock units	1	2	1	1
Diluted weighted-average number of common shares outstanding	416	397	414	375
Basic	$ 0.33	$ 0.22	$ 0.90	$ 0.85
Diluted	0.33	0.21	0.90	0.84
Common Stock, Dividends, Per Share, Declared	$ 1.05	$ 0.95	$ 3.15	$ 2.85