Stock-based Compensation - Options Vested and Expected to Vest (Parenthetical) (Details) - Long-term incentive and director compensation plans - Employee Stock Option shares in Millions, $ in Millions	Dec. 31, 2015 USD ($) shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected forfeitures, effects of which are included (in shares) \| shares	1
Aggregate intrinsic value of stock options outstanding, excluding the effects of expected forfeitures \| $	$ 986

Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant