Schedule of Pre-Tax Income (Loss) Effects of Cash Flow Hedges (Detail) - Cash Flow Hedges - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gain (loss) recognized in OCI	$ 439	$ 418	$ (241)
Gain (loss) reclassified into net income from OCI	208	170	162
Gain (loss) recognized in net income (loss)	0	2	0
Interest Rate Swaps Hedging Assets \| Net Investment Income
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gain (loss) recognized in OCI	482	456	(261)
Gain (loss) reclassified into net income from OCI	196	164	153
Interest Rate Swaps Hedging Assets \| Net Investment Gains (Losses)
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gain (loss) recognized in OCI	0	0	0
Gain (loss) reclassified into net income from OCI	12	6	9
Gain (loss) recognized in net income (loss)	0	0	0
Interest Rate Swaps Hedging Liabilities \| Interest Expense
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gain (loss) recognized in OCI	(38)	(36)	16
Gain (loss) reclassified into net income from OCI	0	0	0
Interest Rate Swaps Hedging Liabilities \| Net Investment Gains (Losses)
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gain (loss) recognized in net income (loss)	0	0	0
Foreign currency swaps \| Net Investment Income
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gain (loss) recognized in OCI	(5)	(2)	4
Gain (loss) reclassified into net income from OCI	0	0	0
Gain (loss) recognized in net income (loss)		0
Foreign currency swaps \| Net Investment Gains (Losses)
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gain (loss) recognized in OCI		0
Gain (loss) reclassified into net income from OCI		0
Gain (loss) recognized in net income (loss)	$ 0	$ 2	$ 0

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- Definition

The effective portion of net gain (loss) reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments.

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The portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments representing (a) the amount of the hedge ineffectiveness and (b) the amount, if any, excluded from the assessment of hedge effectiveness.

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- Definition

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

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