Schedule II - Condensed Financial Information, Notes (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Maturities Of Debt Excluding Capital Leases [Abstract]
Maturities of Debt in 2017	[1]	$ 255
Maturities of Debt in 2018	[1]	131
Maturities of Debt in 2019	[1]	0
Maturities of Debt in 2020	[1]	549
Maturities of Debt in 2021	[1]	378
Maturities of Debt in years after 2021	[1]	3,694
Interest expense on long-term and short-term debt		251	$ 252	$ 265
Interest paid on long-term and short-term debt		244	245	259
Parent Company [Member]
Maturities Of Debt Excluding Capital Leases [Abstract]
Maturities of Debt in 2017		250
Maturities of Debt in 2018		131
Maturities of Debt in 2019		0
Maturities of Debt in 2020		549
Maturities of Debt in 2021		299
Maturities of Debt in years after 2021		3,694
Interest expense on long-term and short-term debt		244	246	$ 252
Intercompany liabilities consisting primarily of loans payable		$ 998	$ 1,086
Average Interest Rate On Intercompany Loan		0.93%	0.60%
Parent Company [Member] | Cigna Holdings, Inc. [Member]
Maturities Of Debt Excluding Capital Leases [Abstract]
Intercompany liabilities consisting primarily of loans payable		$ 658	$ 875

[1] Long-term debt maturity amounts exclude capital leases.