Schedule I (Details) - USD ($) $ in Millions		1 Months Ended	12 Months Ended
	Jul. 23, 2015	Jul. 31, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Condensed Financial Statements, Captions [Line Items]
Cash Dividends Paid to Parent Company by Consolidated Subsidiaries			$ 4,400	$ 4,600
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Payments to Fund Long-term Loans to Related Parties			5,064	436	$ 1,517
Cash Dividends Paid to Parent Company by Consolidated Subsidiaries			4,800	5,500	5,300
Return of capital to parent company			4,375	0	0
Parent Company [Member] | Funding of Amil Share Repurchase [Member]
Condensed Financial Statements, Captions [Line Items]
Payments to Fund Long-term Loans to Related Parties					$ 1,517
Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Other Long-term Debt			$ 164	$ 150
Catamaran [Member]
Condensed Financial Statements, Captions [Line Items]
Payments to Acquire Businesses, Gross	$ 14,300
Catamaran [Member] | Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Payments to Fund Long-term Loans to Related Parties		$ 4,800