CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Tax effects on unrealized gains (losses) resulting from changes in fair value	$ (14)	$ (20)	$ (28)
Tax effects on realized (gains) losses on derivative instruments reclassified into earnings	5	1	12
Tax effects on unrealized gains (losses) on available-for-sale securities	2	(2)	2
Tax effects on change in funded status of post-retirement benefit obligations	$ (2)	$ (5)	$ (3)

Tax effect of the increase (decrease) in the value of the projected benefit obligation and the (increase) decrease in the value of the plan assets resulting from experience different from that assumed or from a change in an actuarial assumption that has not been recognized in net periodic benefit cost.

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Tax effect of the income statement impact of the reclassification adjustment of accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges realized in net income. Also includes reclassification adjustments of an entity's share of an equity investee's deferred hedging gain (loss) realized in net income.

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- Definition

Tax effect of the change in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges. Also includes an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

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- Definition

Tax effect of unrealized holding gain (loss) before reclassification adjustments and transfers on available-for-sale securities.

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