Schedule I - Condensed Financial Information, Balance Sheets - Parentheticals (Details) - shares	Dec. 31, 2018	Dec. 20, 2018	Dec. 31, 2017	Dec. 31, 2016
Consolidated Balance Sheets
Common stock shares issued	381,494,000		296,145,000	0
Common stock shares authorized	600,000,000		600,000,000
Cigna [Member]
Consolidated Balance Sheets
Common stock shares issued	381,000,000
Common stock shares authorized	600,000,000
Old Cigna [Member]
Consolidated Balance Sheets
Common stock shares issued	0		296,145,000	296,145,000
Common stock shares authorized		600,000,000	600,000,000	600,000,000