Acquisition of Aetna - Consideration Transferred (Details) - Aetna Inc. - USD ($) shares in Millions	Nov. 29, 2018	Nov. 28, 2018
Business Acquisition [Line Items]
Cash	$ 48,089,000,000
Common stock (274.4 million shares)	22,117,000,000
Fair value of replacement equity awards for pre-combination services (9.9 million shares)	367,000,000
Effective settlement of pre-existing relationship	(807,000,000)
Total consideration transferred	$ 69,766,000,000
Common stock (in shares)	274.4
Fair value of replacement equity awards for pre-combination services (in shares)	9.9
Common stock, shares outstanding (in shares)		327.6
Weighted average share price of stock (in dollars per share)	$ 80.59
Post-combination compensation costs		$ 232,000,000

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