Shareholders' Equity - Dividends Declared (Details) - USD ($) $ / shares in Units, $ in Millions	Feb. 11, 2016	Dec. 17, 2015	Jul. 30, 2015	May. 20, 2015	Feb. 27, 2015	Mar. 31, 2016
Dividend Per Share (in usd per share)	$ 0.115	$ 0.115	$ 0.115	$ 0.115	$ 0.115	$ 0.115
Dividends, Common Stock, Cash	$ 229	$ 230	$ 229	$ 226	$ 229

Amount of paid and unpaid common stock dividends declared with the form of settlement in cash.

Reference 1: 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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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration