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Amount by which Company may increase the term length of the credit agreement.

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The debt-to adjusted capital ratio which the Company must not exceed in accordance with the terms of the line of credit facility agreement.

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Number of banks participating in revolving credit and letter of credit agreement

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Carrying value as of the balance sheet date of short-term borrowings using unsecured obligations issued by banks, corporations and other borrowers to investors. The maturities of these money market securities generally do not exceed 270 days.

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Face (par) amount of debt instrument at time of issuance.

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Face (par) amount of the original debt instrument that was repurchased.

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Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Schedule I - Condensed Financial Information of Cigna Corporation - Debt (Details)			1 Months Ended	2 Months Ended	3 Months Ended	12 Months Ended
	Dec. 31, 2020 USD ($) bank	Apr. 01, 2020 USD ($)	Oct. 31, 2020 USD ($) bank	Apr. 30, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2020 USD ($) bank	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Mar. 16, 2020 USD ($)
Debt Instrument [Line Items]
Aggregate principal amount of outstanding debt securities under tender offer and optional redemption				$ 3,500,000,000
Aggregate principal amount of outstanding debt securities repurchased under tender offer				1,500,000,000
Aggregate principal amount of outstanding debt securities repurchased under optional redemption				2,000,000,000.0
Debt extinguishment costs				199,000,000		$ 199,000,000	$ 2,000,000	$ 0
Loss on repurchase of debt, after-tax				151,000,000
Notes issued by Express Scripts, Medco and Old Cigna exchanged for Notes issued by Cigna					$ 12,700,000,000
Repayment of long-term debt						8,047,000,000	4,491,000,000	131,000,000
Payments for debt tender and redemption						3,500,000,000
Commercial paper	$ 1,030,000,000				944,000,000	1,030,000,000	944,000,000
Commercial Paper
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 4,250,000,000					$ 4,250,000,000
Average interest rate	0.20%					0.20%
$1,000 million, Floating Rate Notes due 2021
Debt Instrument [Line Items]
Face value	$ 1,000,000,000					$ 1,000,000,000
Revolving Credit Agreement
Debt Instrument [Line Items]
Number of participating banks \| bank	23					23
Maximum borrowing capacity	$ 3,250,000,000					$ 3,250,000,000
Amount by which credit facilty amount can be increased	500,000,000					$ 500,000,000
Amount by which credit facilty term length can be increased						1 year
Revolving Credit Agreement \| Letter of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 500,000,000					$ 500,000,000
Revolving Credit Agreement \| Revolving Credit Facility
Debt Instrument [Line Items]
Leverage ratio covenant	60.00%					60.00%
Outstanding balances	$ 0					$ 0
364-day Revolving Credit Agreement, Maturing October 2021 \| Revolving Credit Facility
Debt Instrument [Line Items]
Number of participating banks \| bank			23
Maximum borrowing capacity			$ 1,000,000,000.0
Credit agreement term			364 days
Leverage ratio covenant	60.00%					60.00%
Outstanding balances	$ 0					$ 0
364-day Revolving Credit Agreement, Maturing October 2020 \| Revolving Credit Facility
Debt Instrument [Line Items]
Maximum borrowing capacity			$ 1,000,000,000.0
Credit agreement term						364 days
Leverage ratio covenant	60.00%					60.00%
Outstanding balances	$ 0					$ 0
364-Day Term Loan \| Line of Credit
Debt Instrument [Line Items]
Face value		$ 1,400,000,000
Credit agreement term		364 days
Repayment of short-term debt	1,400,000,000
Cigna
Debt Instrument [Line Items]
Aggregate principal amount of outstanding debt securities under tender offer and optional redemption				2,900,000,000
Aggregate principal amount of outstanding debt securities repurchased under tender offer				1,300,000,000
Aggregate principal amount of outstanding debt securities repurchased under optional redemption				1,600,000,000
Debt extinguishment costs				171,000,000		171,000,000	0	0
Loss on repurchase of debt, after-tax				$ 124,000,000
Notes issued by Express Scripts, Medco and Old Cigna exchanged for Notes issued by Cigna					$ 12,700,000,000
Repayment of long-term debt						5,996,000,000	$ 3,002,000,000	$ 0
Payments for debt tender and redemption						2,900,000,000
Commercial paper	1,000,000,000.0					1,000,000,000.0
Cigna \| Commercial Paper
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 4,250,000,000					$ 4,250,000,000
Average interest rate	0.20%					0.20%
Cigna \| $1,000 million, Floating Rate Notes due 2021
Debt Instrument [Line Items]
Face value	$ 1,000,000,000.0					$ 1,000,000,000.0
Cigna \| Revolving Credit Agreement
Debt Instrument [Line Items]
Number of participating banks \| bank	23					23
Maximum borrowing capacity	$ 3,250,000,000					$ 3,250,000,000
Amount by which credit facilty amount can be increased	$ 500,000,000					$ 500,000,000
Amount by which credit facilty term length can be increased						1 year
Leverage ratio covenant	60.00%					60.00%
Cigna \| Revolving Credit Agreement \| Letter of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 500,000,000					$ 500,000,000
Cigna \| Revolving Credit Agreement \| Revolving Credit Facility
Debt Instrument [Line Items]
Outstanding balances	$ 0					$ 0
Cigna \| 364-day Revolving Credit Agreement, Maturing October 2021 \| Revolving Credit Facility
Debt Instrument [Line Items]
Number of participating banks \| bank			23
Maximum borrowing capacity			$ 1,000,000,000.0
Credit agreement term			364 days
Leverage ratio covenant	60.00%					60.00%
Outstanding balances	$ 0					$ 0
Cigna \| 364-day Revolving Credit Agreement, Maturing October 2020 \| Revolving Credit Facility
Debt Instrument [Line Items]
Maximum borrowing capacity			$ 1,000,000,000.0
Credit agreement term			364 days
Leverage ratio covenant	60.00%					60.00%
Outstanding balances	$ 0					$ 0
Cigna \| 364-Day Term Loan \| Line of Credit
Debt Instrument [Line Items]
Face value		$ 1,400,000,000
Credit agreement term		364 days
Repayment of short-term debt	$ 1,400,000,000
Senior Notes
Debt Instrument [Line Items]
Face value									$ 3,500,000,000
Senior Notes \| Cigna
Debt Instrument [Line Items]
Face value									$ 3,500,000,000