Shareholders' Equity - Reclassification Out of Accumulated Other Comprehensive Income (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended			12 Months Ended	9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended	3 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 Net gain on investments	Dec. 31, 2013 Net gain on investments	Sep. 30, 2014 Net gain on derivatives	Dec. 31, 2013 Net gain on derivatives	Sep. 30, 2014 Net gains from pension and other postretirement plans	Dec. 31, 2013 Net gains from pension and other postretirement plans	Sep. 30, 2014 Reclassification Out of Accumulated Other Comprehensive Income Net gains from pension and other postretirement plans	Sep. 30, 2014 Reclassification Out of Accumulated Other Comprehensive Income Net gains from pension and other postretirement plans	Sep. 30, 2014 Foreign Exchange Contract Reclassification Out of Accumulated Other Comprehensive Income Net gain on derivatives	Sep. 30, 2014 Foreign Exchange Contract Reclassification Out of Accumulated Other Comprehensive Income Net gain on derivatives	Sep. 30, 2014 Interest Rate Swap Reclassification Out of Accumulated Other Comprehensive Income Net gain on interest rate swap	Sep. 30, 2014 Interest Rate Swap Reclassification Out of Accumulated Other Comprehensive Income Net gain on interest rate swap	Sep. 30, 2014 Unrealized Gain on Investments Reclassification Out of Accumulated Other Comprehensive Income Net gain on investments	Sep. 30, 2014 Unrealized Gain on Investments Reclassification Out of Accumulated Other Comprehensive Income Net gain on investments
Reclassification out of Accumulated Other Comprehensive Income
Investment income	$ 29	$ 26	$ 100	$ 93													$ 13	$ 30
Product sales revenue	3,400	3,165	9,728	9,535									12	15
Cost of product sales	(1,400)	(1,324)	(4,068)	(4,020)									(7)	(7)
Other interest expense	(40)	(58)	(108)	(109)											(6)	(6)
Income (loss) before provision for income taxes	833	820	2,213	2,477									(1)	2
Selling, general and administrative expense											1	1
Provision for income tax	(206)	(181)	(532)	(474)	(72)	(18)	63	66	61	61	0	0	0	0			(5)	(11)
Net income	$ 627	$ 639	$ 1,681	$ 2,003							$ 1	$ 1	$ (1)	$ 2			$ 8	$ 19