Earnings Per Share - Additional Information (Detail) - USD ($) shares in Millions, $ in Millions		3 Months Ended
Apr. 21, 2016	Mar. 31, 2016
Earnings Loss Per Share [Line Items]
Amount remaining under repurchase program		$ 948
Open Market Repurchase Program
Earnings Loss Per Share [Line Items]
Number of shares repurchased		27
Repurchases of common stock		$ 1,500
Subsequent Event \| Open Market Repurchase Program
Earnings Loss Per Share [Line Items]
Repurchases of common stock	$ 100

Equity impact of the cost of common and preferred stock that were repurchased during the period. Recorded using the cost method.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6405813&loc=d3e23239-112655

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

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Balance Type:	debit
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